Magazine et Edition

Volume 71 (2022): Edition 1 (January 2022)

Volume 70 (2021): Edition 1 (January 2021)

Volume 69 (2020): Edition 1 (January 2020)

Volume 68 (2019): Edition 1 (January 2019)

Volume 67 (2018): Edition 1 (February 2018)

Volume 66 (2017): Edition 1 (December 2017)

Volume 65 (2016): Edition 2 (December 2016)

Volume 65 (2016): Edition 1 (December 2016)

Volume 64 (2015): Edition 1-6 (December 2015)

Volume 63 (2014): Edition 1-6 (December 2014)

Volume 62 (2013): Edition 1-6 (December 2013)

Volume 61 (2012): Edition 1-6 (December 2012)

Volume 60 (2011): Edition 1-6 (December 2011)

Volume 59 (2010): Edition 1-6 (December 2010)

Volume 58 (2009): Edition 1-6 (December 2009)

Volume 57 (2008): Edition 1-6 (December 2008)

Volume 56 (2007): Edition 1-6 (December 2007)

Volume 55 (2006): Edition 1-6 (December 2006)

Volume 54 (2005): Edition 1-6 (December 2005)

Volume 53 (2004): Edition 1-6 (December 2004)

Détails du magazine
Format
Magazine
eISSN
2509-8934
Première publication
22 Feb 2016
Période de publication
1 fois par an
Langues
Anglais

Chercher

Volume 55 (2006): Edition 1-6 (December 2006)

Détails du magazine
Format
Magazine
eISSN
2509-8934
Première publication
22 Feb 2016
Période de publication
1 fois par an
Langues
Anglais

Chercher

37 Articles
Accès libre

Application of ISSR Markers to Fingerprinting of Elite Cultivars (Varieties/Clones) From Different Sections of the Genus Populus L.

Publié en ligne: 19 Oct 2017
Pages: 1 - 6

Résumé

Abstract

The Inter-Simple Sequence Repeat (ISSR) was used in this study for genetic fingerprinting and identification of 28 important Populus L. (poplar) cultivars (varieties/ clones), and determination of the genetic relationships among these cultivars. These 28 cultivars belonged to sections Aigeiros, Tacahamaca, Leuce, Turanga, and hybrids between sections Aigeiros and Tacahamaca. Out of 27 ISSR primers tested, eight primers generated clear multiplex profiles. The best three primers produced 154 easily detectable fragments, 129 (84%) of which were polymorphic among the cultivars. Each of these 3 primers produced fingerprint profiles unique to each of the accessions studied, and thus could be solely used for their identification. Twenty-five markers, unique to 10 of the cultivars studied, were detected. These markers may be converted into cultivar-specific probes for identification purposes. Genetic relationships among the cultivars were evaluated by generating a similarity matrix based on the simple matching coefficient and the unweighted pair group method with arithmetic average (UPGMA) dendrogram. The results showed a clear-cut separation of cultivars among different sections of poplar, and were in agreement with the genealogy of the sampled cultivars. The present study shows that ISSR markers could generate abundant polymorphism, are reproducible, and are quick for characterization of poplar cultivars. In the future, the markers used in this study, in combination with other molecular techniques, could provide a useful panel of ISSR markers for largescale DNA fingerprinting of poplar cultivars and determination of the genetic relationships among these cultivars.

Mots clés

  • Poplar
  • ISSR
  • Cultivars identification
  • Genetic relationships
Accès libre

Genetic Variation and Population Structure of Dendropanax morbifera Lev. (Araliaceae) in Korea

Publié en ligne: 19 Oct 2017
Pages: 7 - 13

Résumé

Abstract

Dendropanax morbifera Lev. (Araliaceae) is an economically important tree species because of its role in the production of golden varnishes as well as its use as an ornamental plant. As an endemic tree species of Korea, it is restricted to the southern parts of Korea as isolated populations. In this study, eight natural populations of D. morbifera were investigated by starch-gel electrophoresis in an attempt to determine the extent of its genetic diversity. Out of 8 natural populations, the Suak population in Jeju island showed the lowest level of genetic diversity, while the Wando island population in Jeonnam showed the highest level of genetic diversity. Levels of genetic diversity maintained in D. morbifera (A/L =1.5, P95 = 27.3%, Ho = 0.100, He = 0.095) were notably lower than those of other tree species with wider and more continuous geographic distributions. The reasons for the low level of genetic diversity in D. morbifera might be due to the genetic drift caused by artificial disturbances. Most of the total genetic diversity (96%) was found within the populations. The UPGMA dendrogram based on Nei’s genetic distance did not show any particular geographic patterns. The low level of genetic diversity suggested that there should be an urgent emphasis on the conservation study of this species.

Mots clés

  • Dendropanax morbifera
  • genetic variation
  • natural populations
  • isozymes
Accès libre

Comparison of Phenotype and Combined Index Selection at Optimal Breeding Population Size Considering Gain and Gene Diversity

Publié en ligne: 19 Oct 2017
Pages: 13 - 19

Résumé

Abstract

A breeding program was simulated in this study. Two alternative ways of selecting the breeding population for the following generation was compared. Phenotypic selection, which means to select just on the individual performance, and combined index selection, which means selection on predicted breeding value for each individual obtained by weighting family average and individual phenotype, were compared. The plant number (testing resource) and gene diversity (status number, Ns) were kept constant, but the breeding population size was variable and chosen for maximizing gain for the particular breeding scenario. At low and medium heritability phenotypic selection was inferior to combined index selection. Only when heritability was high phenotypic selection was as efficient (generation 1) as or more efficient (generation 5) than combined index selection. This contrasts to earlier studies done under constant breeding population size, where selection methods appeared similar. The advantage in gain of combined index selection is usually at a larger breeding population size. At limited heritability and breeding population size the difference is considerable. When breeding population size was kept rather small (<100), and the heritability limited, combined index selection can result in slightly higher gain than phenotypic selection at the same gene diversity, but this was at the cost of a much larger breeding population. Phenotypic selection and combined index selection appears as rather similar for many cases in this simple model used in this study. Considering other advantages with phenotypic selection, it may often be regarded as a competitive alternative.

Mots clés

  • heritability
  • genetic gain
  • status number
  • gene diversity
  • breeding population size
  • selection efficiency
Accès libre

Phenotypic Correlation and Path Coefficient Analysis of Nut Yield and Yield Components in Cashew (Anacardium occidentale L.)

Publié en ligne: 19 Oct 2017
Pages: 19 - 24

Résumé

Abstract

Relationships between cashew nut yield and nine agronomic traits comprising seven reproductive (nut and floral) and two vegetative characters were studied in 59 selected cashew genotypes over three production seasons. Phenotypic correlation analysis showed that nuts per panicle (r = 0.844), number of nuts per tree (r = 0.988) and number of hermaphrodite flowers per panicle (r = 0.863) were positively correlated with nut yield and could be used as primary components for improving yield. Although correlation analysis showed insignificant association between nut weight and nut yield, path analysis revealed that the trait had significant positive direct effect (0.317) on nut yield. The subtle indirect effects of nut weight and leaf size on nut yield were more important than their direct effects and could be classified as secondary components. Both the direct and indirect effects of weight of the whole fruit and tree canopy on nut yield were negative and appeared detrimental.

Mots clés

  • Anacardium occidentale
  • Correlation analysis
  • Path analysis
  • Breeding
Accès libre

Variation in Volume Production Through Clonal Deployment: Results From a Simulation Model to Minimize Risk for Both a Currently Known and Unknown Future Pest

Publié en ligne: 19 Oct 2017
Pages: 25 - 37

Résumé

Abstract

A simulation model was developed to examine optimum patterns of deploying selected clones in the hypothetical situations of both a currently known pest and an unknown future pest. We modelled the interactions between Sitka spruce (Picea sitchensis (Bong.) Carr.), an economically important forest tree in British Columbia and the northwestern U.S., and the spruce terminal weevil (Pissodes strobi (Peck)), a major pest in western spruces. The model is combined with the Province of British Columbia’s Tree and Stand Simulator (TASS) model to drive individual tree growth and stand establishment and development. Two clonal-sampling strategies are examined: a randomly drawn set of genotypes or clones, to depict the potential consequences of a new (e.g., exotic) or a previously unimportant natural pest attacking a ‘random’ set of genotypes, and a ‘fixed’ set of clones, emulating a ‘commercial’ or known set of clones for growth and resistance mechanisms. Simulations use a range of numbers of genotypes or clones (2, 6, 18 and 30), and three deployment patterns (a random mixture of ramets, single- clone blocks, and a mosaic of smaller clonal blocks), in one and five hectare (Ha) stands. Total merchantable timber volume on a per Ha basis at harvest age 80 is used to compare the various combinations and schemes. With both random and fixed chosen sets of clones, the random planting pattern (i.e., random mixture of ramets from the clonal set) produced the most volume. Eighteen randomly chosen clones generally produced more volume, than 2, 6 and 30 clones, but differences among 6, 18 and 30 clones were small in most cases, irrespective of planting pattern. For fixed clones, the use of more resistant clones with higher growth potential produced more volume; however, pure clonal blocks of the best clone were not better than a mixture of that clone and an inferior one. Reducing the effects of insect activity and attack on trees, by lowering the average annual temperature in the model, or turning off all insect ‘activity’, increased merchantable volume but did not change the optimum number of clones (~18) or deployment pattern (random mixture). Forestry agencies can weigh these findings against economic advantages of block plantings of similar genotypes, in the choice of an appropriate number of clones and a deployment strategy.

Mots clés

  • clonal forestry
  • genetic diversity
  • risk
  • merchantable volume loss
  • insect resistance
Accès libre

Genetic Variation of Common Ash (Fraxinus excelsior L.) Populations From Provenance Regions in Southern Germany by Using Nuclear and Chloroplast Microsatellites

Publié en ligne: 19 Oct 2017
Pages: 38 - 44

Résumé

Abstract

The genetic structure of 14 populations from three ash provenance regions (Fraxinus excelsior L.) in southern Germany (Aid Infodienst, 2003) is described by analysing the variation of four nuclear and five cpDNA microsatellites. The study of the nuclear microsatellites revealed high levels of genetic diversity but low levels of genetic differentiation, suggesting a high degree of gene flow among regions and/or human interference by introducing plant material coming from different provenances. The distributions of the allele frequencies and the genetic structures at these four microsatellite loci did not allow the identification of distinct provenance regions, although “private alleles” were encountered with moderate to low frequencies (above 5 percent). Specifically, the Rhine valley populations (provenance region 81105) and these from the Swabian Jura and Black Forest (provenance region 81107) revealed private alleles at the two microsatellite loci Femsatl4 and Femsatl12. A more distinct differentiation between provenances was found based on the cpDNA markers. Evidence on genetic delineation and characterization of ash provenances is discussed. Based on these results, provenance regions can be genetically characterised but further analysis of ash populations and of reproductive material (seeds or seedlings) would be of great importance for provenance delineation, as well as gene conservation and sustainable management of ash populations.

Mots clés

  • common ash
  • Fraxinus excelsior
  • genetic variation
  • microsatellites
  • genetic structure
  • differentiation of populations
Accès libre

Phylogenetic Relationship Within Genus Araucaria (Araucariaceae) Assessed by Means of AFLP Fingerprints

Publié en ligne: 19 Oct 2017
Pages: 45 - 52

Résumé

Abstract

Highly polymorphic AFLP markers were applied to analyse the phylogenetic relationships of seven species from three sections within genus Araucaria (Araucariaceae) with cladistic and phenetic approaches. The objectives of the study were to compare the intrageneric relationships within Araucaria assessed by AFLP markers with the classification according to chloroplast DNA sequences and morphological characters. The AMOVA revealed 48% of the variation among species. The results of the principal coordinate analysis revealed three distinct groups: (1) A. angustifolia and A. araucana (= section Araucaria), (2) A. bidwillii (= section Bunya) and (3) A. cunninghamii, A. heterophylla, A. rulei and A. scopulorum (= section Eutacta). In the cladistic and phenetic analyses, phylogenetic trees were subdivided into two sister clades, one comprising the samples from section Eutacta, the other one was divided again into two sister clades corresponding to sections Araucaria and Bunya. These results are congruent with a previous phylogenetic study of the family Araucariaceae based on rbcL sequences and with the classification of genus Araucaria based on morphological characters. Both rbcL sequence data and AFLP analyses do not support section Bunya as one of the oldest sections within genus Araucaria, as suggested by the fossil record. The utility of AFLP markers for phylogenetic analyses is discussed.

Mots clés

  • Araucaria
  • AFLP
  • phylogeny
  • phylogenetic relationships
Accès libre

Short Note: Crossability Between Pinus uliginosa and its Putative Parental Species Pinus sylvestris and Pinus mugo

Publié en ligne: 19 Oct 2017
Pages: 52 - 54

Résumé

Abstract

Results of artificial fertilization of P. uliginosa with P. sylvestris and P. mugo are presented and discussed. P. sylvestris and P. mugo are thought to be the parental species of P. uliginosa. Two grafts of one P. uliginosa clone from Arboretum of the Institute of Dendrology in Kórnik, Poland were used as mother individuals. One individual of P. sylvestris and one individual of P. mugo were the pollen donors. Three mature cones were obtained as the result of artificial pollination of P. uliginosa with P. mugo pollen. Out of 107 seeds, 68 were filled what gives 63%. P. uliginosa conelets pollinated with P. sylvestris pollen were all aborted. Based on obtained data, close phylogenetic relationship between P. uliginosa and P. mugo complex is suggested.

Mots clés

  • P. uliginosa
  • P. sylvestris
  • P. mugo
  • hybridization
  • pollination
  • crossability
Accès libre

DNA From Ancient Cedar Wood From King Midas’ Tomb, Turkey, and Al-Aksa Mosque, Israel

Publié en ligne: 19 Oct 2017
Pages: 54 - 62

Résumé

Abstract

Ancient Taurus cedar (Cedrus libani A. Rich) wood samples from the Tumulus of King Midas at the Gordion archaeological site (about 2700 years old), near Ankara, Turkey, and from the Al-Aksa Mosque (about 1500 to 1900 years old), Jerusalem, Israel, were characterized by studying the sequences of ribosomal DNA (rDNA) internal transcribed spacers (ITS1 and ITS2). After extraction of the DNA, the ITS regions were amplified utilizing the polymerase chain reaction, followed by sequencing, BLAST searches for similar sequences, and phylogenetic analyses. Fifty-six sequences were obtained. In BLAST searches of existing sequence databases, most were closest to those from humans and fungi. However, two sequences exhibited similarities with conifer ITS sequences. One was an ITS1 region from the Gordion wood specimen, and the other one was an ITS2 region from the Al-Aksa wood specimen. Phylogenetic analyses indicated that both were closest to Taurus cedar (C. libani, also known as Lebanon cedar) ITS sequences from three recent samples of Taurus cedar from two sites in Turkey. However, they exhibited many differences from the recent C. libani rDNA ITS sequences from Turkey, probably due to degradation of the DNA in the ancient samples. The implications of the results on future studies are discussed.

Mots clés

  • Ancient DNA
  • Midas
  • Gordion
  • Cedrus libani
  • wood
Accès libre

Stepwise Penalty Index Selection from Populations with a Hierarchical Structure

Publié en ligne: 19 Oct 2017
Pages: 62 - 70

Résumé

Abstract

By adding a penalty to a candidate’s breeding value for its relationship with the selected individuals, two indexes were constructed as criteria for stepwise selection of superior individuals from populations with a hierarchical structure. The relationship was expressed in terms of either family contribution or group coancestry. One of the indexes was derived from an optimal selection model. A stepwise procedure that screened superior individuals one by one was introduced to make selection based on these indexes possible. Two penalty selection methods exclusively maximized gain at given coancestry. Both methods produced all identical solutions in most of the populations simulated, and were nearly equivalent in the remaining populations, particularly when heritability was high and the population structure was simple. A better balance between gain and coancestry following penalty index selection can be obtained by avoiding the two extreme solutions: combined- index and within-family selection, and using simple mating designs rather than complex ones.

Mots clés

  • breeding value
  • penalty index
  • family contribution
  • gain
  • group coancestry
Accès libre

Accuracy of Ranking Individuals in Field Tests of Different Designs: A Computer Simulation

Publié en ligne: 19 Oct 2017
Pages: 70 - 77

Résumé

Abstract

A computer simulation was conducted to investigate the accuracy of ranking individual trees in field tests of different designs. A test population that consists of 900 trees from 45 full-sib families generated by three 6-parent disconnected half-diallels was considered. One incomplete block design with single-tree plots and four complete block designs with 1, 2, 4, and 10-tree row plots were examined. Various narrow-sense heritabilities, site variation patterns (patch sizes and gradient slopes), and two levels of dominant to additive genetic variance ratios (0 and 0.30) were evaluated. Results indicate that the accuracy of ranking depends more on the heritability of the trait and less on the magnitude of the dominant genetic variance, site variation patterns, and field designs. With patchy site variation, differences in ranking accuracy were observed for different designs, but became smaller with higher heritabilities. Impact of environmental gradient on the accuracy of individual ranking was negligible. Incomplete block design with single-tree plots (ICB1) provided the most accurate ranking when heritability was low while complete block design with 2-tree plots (RCB2) appeared to be the best when heritability was high. Large row plot designs were among the least effective in all the simulated scenarios. For traits with medium heritabilities, the statistical efficiencies of ICB1 and RCB with 1 and 2-tree plots are comparable.

Mots clés

  • breeding value
  • progeny testing
  • field design
  • ranking accuracy
  • computer simulation
Accès libre

Genetic Parameters and Strategies for Genetic Improvement of Stiffness in Radiata Pine

Publié en ligne: 19 Oct 2017
Pages: 77 - 84

Résumé

Abstract

The two main objectives of this study were: (1) to determine how early is it possible to undertake selection to improve the stiffness of corewood; (2) to determine if the selection based on corewood stiffness could also improve outerwood stiffness, and vice versa. Breastheight data from two progeny trials of Pinus radiata D. Don were used. In the first trial (age 30 years), data on Silviscan predicted stiffness (MoE) was obtained for each growth ring on each core sample from 50 open-pollinated families. In the second trial (age 14 years), data on static-bending MoE was obtained using clearwood sticks (300 × 20 × 20 mm) cut from each tree from 18 control-pollinated families. MoE varied from 3.5 GPa in rings 1-5 to about 17 GPa in rings 21-25. Coefficients of variation of corewood and outerwood MoE were about 20-30% and 15-20% respectively. Estimates of narrowsense heritability for MoE were generally higher (0.50-0.70) in the corewood compared with the outerwood (0.15-0.30). Early selection for MoE could yield substantial gain in corewood MoE but only small gains, if any, in outerwood MoE (especially for rings 21-30). Estimated genetic correlations between density and stiffness appeared moderate in the corewood zone, but high in the outerwood zone. Selection based on density (using 5-mm cores) and acoustic stiffness (using standing tree tools), assessed at age 6-7 years, appeared to be a good option to improve both corewood and outerwood stiffness.

Mots clés

  • Stiffness
  • sound velocity
  • wood density
  • heritability
  • breeding strategy
  • genetic correlation
  • age-age correlation
  • early selection
  • Pinus radiata
Accès libre

Estimating Genetic Parameters for Wood Density of Scots Pine (Pinus sylvestris L.)

Publié en ligne: 19 Oct 2017
Pages: 84 - 92

Résumé

Abstract

Wood density was analysed and annual ring width was measured on increment cores from 1400 trees in a 30-year-old full-sib progeny test of Scots pine (Pinus sylvestris L.) in north Sweden. Genetic parameters for wood density were analysed separately for ten outer annual rings, and for simple averages of the five most recent years. The evaluation included genetic correlations with height and stem diameter. Heritabilities of density estimated separately for each annual ring was 0.14-0.26 without any age trend, and jointly for the ten or five latest rings 0.30-0.33; for height growth it was 0.30-0.42 and for stem diameter 0.11-0.13. Additive genetic correlations with height and stem diameter were negative with the simplest statistical model (ȓA = -0.425 and 0.511, respectively) but vanished or diminished when ring width was added as covariate. Density breeding values calculated for the parent trees for each of ten annual rings separately varied considerably between parent trees and between years, tending to increase with increasing age, with a substantial increase between the ages 14 to 16 years from the pith. This age fits well with literature data on the change from juvenile to mature wood. The genetic correlation for wood density between rings from different years was high: ȓA = 0.8 ten years apart, increasing to 1.0 for neighbouring rings. The high genetic correlations for wood density between the innermost and outermost annual rings indicate possible strong covariation between juvenile and/or transition wood and mature wood. The annual variation in wood density in relation to genetic regulation, phenology, environmental conditions, and development from juvenile to mature age is discussed.

Mots clés

  • annual ring density
  • annual ring width
  • breeding value
  • genetic correlation
  • heritability
  • juvenile wood
  • mature wood
  • multitrait REML
  • repeated-measurement model
  • wood density
Accès libre

Cytogenetic Effect of Radiation in Seed of Oak (Quercus robur L.) Trees Growing on Sites Contaminated by Chernobyl Fallout

Publié en ligne: 19 Oct 2017
Pages: 93 - 101

Résumé

Abstract

The Chernobyl accident was one of the largest man made environmental disasters and had significant consequences for people, animal and plants, particularly on land contaminated by radionuclides. Common oak (Quercus robur L.) is the main forest species on land contaminated by Chernobyl fallout areas in the Voronezh region. Therefore it is very important to know how irradiation of oak trees will affect the quality of oak progeny in future consequently. Cytogenetic characteristics such as mitotic activity, level and spectrum of mitotic disturbances, frequency of the cells with persistent nucleoli in the stages of metaphase, anaphase, telophase and multinuclei in interphase cells were investigated in progeny of common oak (Quercus robur L.) trees subjected to different degrees of radioactive contamination. In progeny growing under the influence of this radioactive contamination we observed variability of such cytogenetic characteristics as mitotic activity. However, the variability of this trait was also connected to fluctuations in the weather. The duration of mitotic stages (which may be connected with disturbance of spindle division formation and absence of cytotomy) also varied. An increase in chromosomal bridges among other types of mitotic abnormalities may be considered a result of increases in the meristematic cells repair activities. Activity of some dormant nucleolus organizer regions was also observed. The level of pathological mitoses increased in particular years and was decreased in others. Thus irradiation induces instability of cytogenetic characteristics in oak progeny that produces a type of “wave kinetics” in the mutation rate. This makes them more sensitive to environmental conditions. Therefore we do not recommend to use the oak seeds collected from irradiated areas for reforestation because undesirable genetic changes may have occurred in them.

Mots clés

  • Quercus robur L. (common oak)
  • mitotic activity
  • mitotic disturbances (mitotic pathology)
  • nucleolus
  • radioactive irradiation
  • Chernobyl Accident
Accès libre

Identification of Atractylodes japonica and A. macrocephala by RAPD analysis and SCAR Markers

Publié en ligne: 19 Oct 2017
Pages: 101 - 105

Résumé

Abstract

The Chinese plant, “Packchul”, (Atractylodes japonica or A. macrocephala), is a very important Chinese medicinal herb plant and is called Sabju in Korea. The levels of the active components are different between these two species, but these medicines are sold in Korean herbal markets without discrimination. This study was carried out to develop a method that could be used to discriminate between A. japonica and A. macrocephala based on molecular markers. To discriminate between A. japonica and A. macrocephala, RAPD analyses were used to develop SCAR markers. Eighteen species-specific RAPD bands were obtained from 52 OPERON and URP primer sets. Two SCAR markers were developed from these RAPD clones. Both SCAR markers were cloned into pGEM-T-Easy vectors and then subjected to nucleotide sequence analysis and designated AjR1 (1,117 bp) and AmR1 (1,325 bp). These two markers were sufficient to discriminate between samples of A. japonica and A. macrocephala.

Mots clés

  • Atractylodes japonica
  • A. macrocephala
  • RAPD
  • SCAR
Accès libre

Genetic Diversity of Two Evergreen Oaks [Quercus suber (L.) and Quercus ilex subsp. rotundifolia (Lam.)] in Portugal using AFLP Markers

Publié en ligne: 19 Oct 2017
Pages: 105 - 118

Résumé

Abstract

The genetic variability of cork oak (Quercus suber, L.) in Portugal was evaluated by AFLP using five primer combinations. Three hundred and thirteen trees from three geographically contrasting regions exhibited a high level of genetic variation. The genetic profile of each individual is composed of 291 loci, randomly positioned in the genome and consists of monomorphic and polymorphic fragments. Similarities and dissimilarities among the individuals were quantitatively evaluated by numerical taxonomy. The overall sample shows a proportion of AFLP polymorphic markers of 71%, denoting a high level of variability. Ninety percent of the polymorphic markers identified in cork oak genotypes are uniformly distributed throughout the cork oak populations of Algarve, Alentejo and Trás-os-Montes regions. The coefficients of genetic similarity vary from 0.61 to 0.88 implying that 60% of fragments found are common. A sample of 52 holm oak [Quercus ilex subsp. rotundifolia (Lam.)] trees from overlapping areas was also analysed by AFLP with the same five primer combinations. However the codification of markers together with those selected on cork oak profiles was feasible with only one primer combination due to an apparent much higher polymorphism. AFLP and numerical taxonomy analysis enabled to differentiate the taxa and showed that the level of similarity observed between the profiles of the individuals from holm oak species was lower than that observed in cork oak, implying that apparently the degree of polymorphism is higher in Q. ilex subsp. rotundifolia than that quantified in Q. suber. A Bayesian approach was used to assess Q. suber total genetic diversity (Ht = 0.2534, P < 0.001) of which 1.7% (Fst = 0.0172, P < 0.001) was assigned to differences among populations. Analysis of molecular variance (AMOVA) showed that most genetic variation is comprised within populations (96%) while 3.6% is among populations (Φst = 0.036, P < 0.001). Differences among populations within geographic regions account for 2.6% (Φsc = 0.026, P < 0.001) of the total variation and only 1.3% (Φct = 0.013, P = 0.007) is attributed to variation among regions denoting little differentiation of populations over a range of 700 km.

Mots clés

  • AFLP
  • genetic diversity
  • genetic introgression
  • Quercus suber (L.)
  • Quercus ilex subsp. rotundifolia (Lam.)
Accès libre

Identification of Species-Diagnostic ISSR Markers for Six Eucalyptus Species

Publié en ligne: 19 Oct 2017
Pages: 119 - 122

Résumé

Abstract

Eucalyptus is planted worldwide for raw material in paper and rayon industry. It is a potential out-crosser and the natural populations are highly heterogeneous displaying strong inbreeding depression. Eucalyptus hybrids have been intensively utilized for their vigor, higher wood quality and resistance to diseases. Identification of species for hybridization is predominantly based on morphological characters and is not always reliable. Hence, DNA marker based species identification and hybrid validation is an important and efficient tool in breeding programs. In the present study, attempts were made to identify species - diagnostic markers for six eucalypt species (E. camaldulensis Dehnh, E. citriodora Hook, E. grandis W. Hill ex Maiden, E. pellita F. Muell, E. tereticornis Sm and E. urophylla S.T. Blake) using ISSR-PCR fingerprints. PCR amplification using seven ISSR primers resulted in significant polymorphism among the population from different species. E. citriodora and E. tereticornis showed monomorphic frequency of maximum 37.5% and minimum 14.3% respectively. Twenty species-diagnostic markers were identified for E. camaldulensis, E. citriodora, E. grandis and E. urophylla while no marker was detected for E. pellita and E. tereticornis. A maximum of eleven and a minimum of one species-diagnostic marker were recorded for E. citriodora and E. camaldulensis respectively. Among the twenty markers, nine were present in all the individuals of a particular species.

Mots clés

  • DNA
  • Inter-Simple-Sequence-Repeat markers
  • Eucalypt
  • Fingerprinting
  • Tree breeding
Accès libre

Identification of European and Japanese Larch and Their Interspecific Hybrid with Morphological Markers: Application to Young Seedlings

Publié en ligne: 19 Oct 2017
Pages: 123 - 134

Résumé

Abstract

Open-pollinated hybridisation seed orchards of European and Japanese larches produce mixed progenies combining a highly variable proportion of hybrids along with pure parental species. For several reasons, it is desirable to identify and to sort out hybrids from pure species at the seedling stage. Taxa identification of 1-2 yr-old seedlings was attempted using non-destructive assessment of several traits, including morphology, phenology, growth and architecture parameters. Two sets of progenies originating from 10 open-pollinated hybridisation seed orchards were used, relying in a first step on taxa identification of individual seedlings with diagnostic molecular markers. Based on 21 traits assessed, some clear trends in pure species and hybrid features were apparent but due to the large and overlapping ranges of taxa characteristics, no single parameter allowed unambiguous identification of taxa. Combination of traits through linear discriminant analysis made possible correct classification of 90.2% to 98.6% of individuals depending on the orchard although there were a few problematic orchards. Two traits appeared particularly pertinent for discriminating young plants taxa, namely 1st-yr leaf retention (marcescence) and the bark colour of 2nd-year shoot increments. Results were corroborated using progenies from several orchards and over two experimental periods.

Mots clés

  • Larix
  • taxonomy
  • hybrid
  • seedling
  • morphology
  • phenology
  • growth
  • linear discriminant analysis
  • seed orchard
Accès libre

Early Selection of Douglas-Fir across South Central Coastal Oregon, USA

Publié en ligne: 19 Oct 2017
Pages: 135 - 141

Résumé

Abstract

Details are given of three first-generation progeny tests (CB1, CB2 and CB3) of coastal Douglas-fir (Pseudotsuga menziesii [MIRB.] FRANCO var. menziesii) planted in the Coos Bay region of south-central coastal Oregon in 1973. The three tests included 15 polymix families based on a 10-pollen mix, and 27 families openpollinated on the ortet. The present study gives heritabilities and additive genetic correlations for growth measured between two and 17 years after planting. Correlated responses are estimated for volume at 17 years from early selection for height and diameter. Between four and 17 years after planting the individual heritability (h2) of height of coastal Douglas-fir across the Coos Bay tests was quite stable between h2 = 0.18 and 0.22. The heritability of stem diameter age-forage was consistently much lower than for height. In the critical age range for early selection between five and 10 years the individual heritability of diameter ranged from h2 = 0.07 to 0.10. The additive genetic correlations involving volume-17 and height or diameter increased to high values of rA = 0.80 to 0.84 between eight to 10 years after planting. Before seven years the absolute values of juvenilemature correlations were much lower. The higher heritability of height made this trait the best criterion for early indirect selection to improve mature stem volume growth. Across these Coos Bay tests, early selection on stem height measured at 5-8 years after planting was estimated to produce almost 40% more gain per year in volume-17 compared with direct selection at 17 years on volume-17 itself. The recommendation for maximizing gain per year in mature volume of coastal Douglas-fir at Coos Bay is to select on height at 7-8 years when the mean height of trees in tests should be around 4.5 to 5.5 meters.

Mots clés

  • Douglas-fir
  • growth
  • heritability
  • juvenile-mature correlation
  • early selection efficiency
Accès libre

Bud Removal Affects Shoot, Root, and Callus Development of Hardwood Populus Cuttings

Publié en ligne: 19 Oct 2017
Pages: 141 - 148

Résumé

Abstract

The inadvertent removal and/or damage of buds during processing and planting of hardwood poplar (Populus spp.) cuttings are a concern because of their potential impact on shoot and root development during establishment. The objective of the current study was to test for differences in shoot dry mass, root dry mass, number of roots, length of the longest root, and callus dry mass among ten poplar clones subjected to three pre-planting bud removal intensities (0%, 50%, 100%). The ten clones and their genomic groups were: DM115 (P. deltoides Bartr. ex Marsh× P. maximowiczii A. Henry); DN34, I45-51 (P. deltoides× P. nigra L.); NC13446, NC13563, NC13649, NC13685, NC13747 [(P. trichocarpa Torr. & Gray× P. deltoides)× P. deltoides]; and NM2, NM6 (P. nigra× P. maximowiczii). Cuttings, 20 cm long, were processed from shoots collected January 2005 from stool beds established at Hugo Sauer Nursery in Rhinelander, Wisconsin, U.S.A. (45.6 °N, 89.4°W). We measured the traits from harvested cuttings after 14 d of growth. The treatment× clone interaction governed shoot dry mass (P < 0.0001). In general, the top four clones (DM115, DN34, NM2, NM6) exhibited the best shoot dry mass with 0% and 50% of buds removed, while differences among treatments for the remaining clones were negligible. Clones differed for root dry mass (P < 0.0001), while the treatment and clone main effects governed number of roots (P = 0.0126, P < 0.0001, respectively) and length of the longest root (P = 0.0077, P < 0.0001, respectively). Cuttings subjected to the 0% treatment exhibited the greatest number of roots, while cuttings of the 0% and 50% treatment exhibited the greatest length of the longest root. The treatment× clone interaction governed the presence of callus (P = 0.0161), while clones differed for callus dry mass (P < 0.0001). Bud removal did not affect root biomass but it did impact root initiation. Unlike shoot dry mass, the response to removing buds for all rooting traits was not clone-specific. From a practical standpoint, inadvertently damaging and/or removing ≤ 50% of the buds during processing and planting should not be a concern for establishment.

Mots clés

  • adventitious rooting
  • hybrid poplar
  • preplanting treatment
  • vegetative propagation
  • Populus deltoides
  • P. nigra
  • P. maximowiczii
  • P. trichocarpa
Accès libre

Phenology and Control Pollination Studies in Casuarina equisetifolia Forst

Publié en ligne: 19 Oct 2017
Pages: 149 - 155

Résumé

Abstract

Studies on phenology, floral biology and seed production were conducted in two provenance trials and a clonal hedge orchard of C. equisetifolia. Observations in seventeen populations indicate that predominant dioecy with low proportion of monoecy as the commonest sexual strategy. Flowering occurs twice in a year coinciding with the South West and North East monsoons. C. equisetifolia exhibits strong anemophilous adaptations such as very high pollen output, reduced flowers with large stigmatic area and light weighing winged fruits. Pollen is viable up to 99%, storable in 4°C up to three months with no loss in fertility. Trees start reproducing within two years of planting. Local land races produce ten to twenty times higher seeds than the recent introduced natural provenances and exotic landraces. Controlled pollination resulted in lower seed set than observed in open pollination. Selfing leads to normal seed set in monoecious trees. Inter specific cross with C. junguhuhniana pollen parent results in viable progeny.

Mots clés

  • Anemophily
  • Casuarina
  • cone
  • landrace
  • phenology
  • provenance
  • pollination
  • reproduction
  • seed
Accès libre

Segregation and Linkage Relationships of Allozymes in Pinus Brutia Ten

Publié en ligne: 19 Oct 2017
Pages: 155 - 160

Résumé

Abstract

Female gametophytes of Pinus brutia Ten. were analyzed to study Mendelian segregation and linkage among allozyme loci in a seed orchard composed of 28 clones. Isozyme variants of nine enzyme systems encoding 14 loci from megagametophytes were assayed by starch gel electrophoresis. While six of the 14 loci were monomorphic, the remaining eight were polymorphic. Analysis of observed segregation ratios of all polymorphic loci except for Sdh1, showed a good fit to the 1:1 ratios expected for Mendelian inheritance. Linkage relationships of the eight polymorphic allozyme loci were analyzed by testing 23 of the 28 possible two-locus combinations. Two-locus segregations in three pairs (Got2- Mdh1, Got2-Pgi2 and Pgd3-Sdh1) were significantly heterogeneous (P ≤ 0.05). Relatively weak linkage was observed between only one pair of genes (Adh2:Got2). Recombination fraction for Adh2:Got2 was found to be 0.24 (± 0.06).

Mots clés

  • linkage
  • allozyme
  • inheritance
  • seed orchard
  • Pinus brutia
Accès libre

Genetic Diversity and Gene Flow of Quercus crispula in a Semi-Fragmented Forest Together With Neighboring Forests

Publié en ligne: 19 Oct 2017
Pages: 160 - 169

Résumé

Abstract

The genetic diversity and differentiation in Quercus crispula populations in the Chichibu Mountains, central Japan, were evaluated using six microsatellite markers. Gene flow into a 2500-m2 semi-fragment of a natural forest from the neighboring natural forest at a distance of more than 50m was also evaluated using parentage analysis. All five populations in the mountains had similar levels of genetic diversity (He = 0.752-0.792), and the level of population differentiation was low (FST = 0.016). The semi-fragmented stand showed similar genetic diversity with the neighboring unfragmented forests, and Hardy-Weinberg disequilibrium was not found (FIS = 0.083 in adults, 0.025 in seedlings). In the semifragment, 70 seedlings were examined; according to the parentage analysis, eight of the 70 seedlings (ca. 11%) had neither of the parent trees in this fragment. These seeds must have been transported from a distance of more than 50 m; therefore, there could be a possibility that the seeds were dispersed by birds. A similar trend of seed flow into the fragment was also confirmed by genotyping endocarps of hypogeal cotyledons, while more frequent seed flow was found in the neighboring unfragmented forest. Of the remaining 62 seedlings, the maternal trees (but not the paternal trees) of 29 seedlings and both parent trees of 33 seedlings were detected in the semi-fragment. These results indicate that the gene flow among the populations occurs frequently via pollen dispersal and occasionally via seed dispersal and that, at least the current levels of genetic diversity have been maintained in such fragmented forests.

Mots clés

  • forest fragmentation
  • microsatellites
  • parentage analysis
  • Quercus crispula
Accès libre

Date of Shoot Collection, Genotype, and Original Shoot Position Affect Early Rooting of Dormant Hardwood Cuttings of Populus

Publié en ligne: 19 Oct 2017
Pages: 169 - 182

Résumé

Abstract

Identifying superior combinations among date of dormant- season shoot collection, genotype, and original shoot position can increase the rooting potential of Populus cuttings. Thus, the objectives of our study were to: 1) evaluate variation among clones in early rooting from hardwood cuttings processed every three weeks from shoots collected throughout the dormant season and 2) evaluate variation among genomic groups in early rooting of the same cuttings while testing for differences among three parental shoot positions (apical, middle, basal). We tested 22 clones belonging to six genomic groups ([P. trichocarpa Torr. & Gray × P. deltoides Bartr. ex Marsh] × P. deltoides ‘BC’, P. deltoides ‘D’, P. deltoides × P. maximowiczii A. Henry ‘DM’, P. deltoides × P. nigra L. ‘DN’, P. nigra × P. maximowiczii ‘NM’, P. trichocarpa ‘T’). Cuttings, 20 cm long, were processed from shoots collected every three weeks beginning 1 Dec. 2003 until 9 Apr. 2004 from stool beds established at Hugo Sauer Nursery in Rhinelander, Wisconsin, USA (45.6 °N, 89.4°W). We measured number of roots and root dry weight from harvested cuttings after 14 days of growth. The interaction between date of shoot collection and clone governed both traits (P < 0.0001). In general, clones exhibited the best rooting when cuttings were processed from shoots collected on or after 23 Feb. 2004. The interaction between date of shoot collection, genomic group, and shoot position governed number of roots (P = 0.0348) and root dry weight (P = 0.0262). There was broad variation in number of roots and root dry weight of apical, middle, and basal cuttings within and among genomic groups across dates of shoot collection, with 15 Mar. 2004 being an important date because differences among positions began to develop or changed relative to earlier dates. Thus, for increased plantation establishment potential with similar genotypes, we recommend collecting stool shoots no sooner than the end of February and matching cuttings of specific shoot positions to each genomic group.

Mots clés

  • Populus genomic groups
  • hybrid poplar
  • adventitious rooting
  • genotype x environment interaction
  • whip
  • stool bed
Accès libre

Early Selection of Radiata Pine

Publié en ligne: 19 Oct 2017
Pages: 182 - 191

Résumé

Abstract

Additive genetic, dominance genetic and phenotypic variances and corresponding correlations were estimated for growth data collected from disconnected half-diallel progeny trials involving 25 Pinus radiata D. DON parents and replicated across two sites in central North Island, New Zealand. Sectional area of stem was measured at three, seven, 10 and 13 years after planting at both sites, and height at three and 10 years at one site. Sectional area at three years exhibited similar levels of estimated additive (σA2) and dominance (σD2) genetic variance. However, levels of σD2 remained approximately constant between three and 13 years while σA2 increased substantially. Thus, sectional-area growth changed from being under equal additive and dominance genetic control at three years to almost complete additive genetic control from seven to 13 years. The greater increase in additive variance relative to phenotypic variance led to increases in individual heritability from 0.16 to 0.28 to 0.35 for sectional-area increments between 3-7, 7-10 and 10-13 years, respectively. Height growth exhibited negligible levels of σD2 for the three- and 10-year measurements. The early sectional-area increment between 3-7 years showed an estimated additive genetic correlation of 0.87 with “mature” sectional area at 13 years. Subsequent sectional-area increments between 7-10 and 10-13 years showed estimates of additive genetic correlations of 0.99 with sectional area at 13 years. Dominance genetic correlations were much lower in magnitude, reflecting inconsistent dominance effects over time.

Mots clés

  • Pinus radiata
  • additive variation
  • dominance variation
  • juvenile-mature correlation
  • heritability
Accès libre

Comparison Between Open Pollinated Progenies and Hybrids Performance in Eucalyptus grandis and Eucalyptus urophylla

Publié en ligne: 19 Oct 2017
Pages: 192 - 196

Résumé

Mots clés

  • reciprocal recurrent selection
  • half-sib progenies
  • full-sib progenies
  • wood basic density
  • genetic correlation
  • genetic variance
  • heterosis
  • Eucalyptus
Accès libre

Genetic Variability and Structure of The Wild Service Tree (Sorbus torminalis (L.) Crantz) in Poland

Publié en ligne: 19 Oct 2017
Pages: 197 - 202

Résumé

Abstract

Sorbus torminalis is a rare forest tree species in Poland. Allelic and genotypic structures at 25 isozyme gene loci were observed in 20 populations from Poland, situated mainly along a latitudinal gradient. Levels of genetic diversity were high both at the species level (P = 44%, He = 0.435) and within populations (mean P = 40.8%, mean He = 0.373). Levels of differentiation among populations were relatively high (FST = 0.17) and a noticeable geographic structure of this differentiation was detected. The population in the ‘Brekinia’ reserve had a unique genetic structure of a clonal population and was the most distinct from the other populations.

Mots clés

  • electrophoresis
  • isozymes
  • genetic diversity
  • population differentiation
  • Sorbus torminalis
Accès libre

Parental and Consensus Linkage Maps of Eucalyptus globulus Using AFLP and Microsatellite Markers

Publié en ligne: 19 Oct 2017
Pages: 202 - 217

Résumé

Abstract

Parental and consensus maps were constructed in an F2 inter-provenance cross of Eucalyptus globulus, using amplified fragment length polymorphism (AFLP) and microsatellite (or simple sequence repeats [SSR]) markers. The female map had 12 linkage groups and 118 markers, comprising 33 SSR and 85 AFLP loci. The male map had 14 linkage groups and 130 markers comprising 36 SSR and 94 AFLP loci. The integrated map featured 10 linkage groups and 165 markers, including 33 SSR and 132 AFLP loci, a small 11th group was identified in the male parent. Moderate segregation distortion was detected, concentrated in gender specific groups. The strongest distortion was detected in the female parent for which causal mechanisms are discussed. The inclusion of SSR markers previously mapped in several different eucalypt species within the subgenus Symphyomyrtus (E. globulus, E. camaldulensis, and predominantly E. grandis and E. urophylla), allowed comparison of linkage groups across species and demonstrated that linkage orders previously reported in E. globulus, E. grandis and E. urophylla were largely conserved.

Mots clés

  • Linkage map
  • Eucalyptus globulus
  • SSR
  • AFLP
  • comparative mapping
Accès libre

Genetic Variation and Correlations between Growth and Wood Density of Calycophyllum spruceanum at an Early Age in the Peruvian Amazon

Publié en ligne: 19 Oct 2017
Pages: 217 - 228

Résumé

Abstract

Calycophyllum spruceanum (Benth.) Hook. f. ex K. Shum. is an important timber-tree species in the Peruvian Amazon Basin. As farmers and industry often use wood from young trees, it is important to investigate variation in juvenile wood properties in this species. A provenance/progeny test was established to evaluate genetic variation in growth and wood properties of young trees, the strength of their genetic control as well as their interrelationships both at the genetic and the phenotypic level in different planting zones. In this paper, results are presented for tree height and stem diameter (near ground level) at 16, 28 and 39 months; and stem diameter and basic density of the wood at breast height at 39 months. Significant variation due to provenances and especially due to families within provenances was found in growth and wood density. Phenotypic and genetic correlations indicated that larger trees tended to have denser wood. Wood density had higher heritability than height and diameter; and genetic control over height, diameter and density was generally highest in the planting zone where trees grew most rapidly.

Mots clés

  • provenance
  • family
  • environment
  • heritability
  • phenotypic and genetic correlations
  • juvenile wood
Accès libre

Construction of Microsatellite Linkage Maps for Corymbia

Publié en ligne: 19 Oct 2017
Pages: 228 - 238

Résumé

Abstract

The genus Corymbia is closely related to the genus Eucalyptus, and like Eucalyptus contains tree species that are important for sub-tropical forestry. Corymbia’s close relationship with Eucalyptus suggests genetic studies in Corymbia should benefit from transfer of genetic information from its more intensively studied relatives. Here we report a genetic map for Corymbia spp. based on microsatellite markers identified de novo in Corymbia sp or transferred from Eucalyptus. A framework consensus map was generated from an outbred F2 population (n = 90) created by crossing two unrelated Corymbia torelliana × C. citriodora subsp. variegata F1 trees. The map had a total length of 367 cM (Kosambi) and was composed of 46 microsatellite markers distributed across 13 linkage groups (LOD 3). A high proportion of Eucalyptus microsatellites (90%) transferred to Corymbia. Comparative analysis between the Corymbia map and a published Eucalyptus map identified eight homeologous linkage groups in Corymbia with 13 markers mapping on one or both maps. Further comparative analysis was limited by low power to detect linkage due to low genome coverage in Corymbia, however, there was no convincing evidence for chromosomal structural differences because instances of non-synteny were associated with large distances on the Eucalyptus map. Segregation distortion was primarily restricted to a single linkage group and due to a deficit of hybrid genotypes, suggesting that hybrid inviability was one factor shaping the genetic composition of the F2 population in this inter-subgeneric hybrid. The conservation of microsatellite loci and synteny between Corymbia and Eucalyptus suggests there will be substantial value in exchanging information between the two groups.

Mots clés

  • Corymbia torelliana
  • Corymbia citriodora subsp. variegata
  • genetic map
  • hybrid inviability
  • genetic marker
  • tree improvement
  • marker-aided selection
Accès libre

Short Note: High Throughput Microsatellite Genotyping in Oak Species

Publié en ligne: 19 Oct 2017
Pages: 238 - 240

Résumé

Abstract

Microsatellites are widely used markers for multiple purposes in oaks. We describe a complete procedure for cheap DNA extraction and fast microsatellites genotyping by multiplex PCR. 10 loci were selected to form two multiplex kits including three loci that show a high differentiation between Quercus robur and Q. petraea. The loci were tested in three oak species and show a high mean genetic diversity of 0.84. The cumulative exclusion probability for parentage analysis was 0.999977 for single parent and 1.0 for paternity. Finally, the relatively high differentiation coefficient (Gst = 0.04) will facilitate species assignment based on genotypes in oaks.

Mots clés

  • microsatellites
  • multiplex PCR
  • Quercus
  • genetic assignment
  • parentage analysis
Accès libre

GMO Trees: Substantial promise but serious obstacles to commercialization

Publié en ligne: 19 Oct 2017
Pages: 241 - 252

Résumé

Mots clés

  • Genetic engineering
  • trees
  • transgenic
  • harvests
Accès libre

Genetic Engineering in Conifer Plantation Forestry

Publié en ligne: 19 Oct 2017
Pages: 253 - 262

Résumé

Abstract

In this review we examine the history and progression of conifer genetic engineering. The review includes the methods used, the conifer species transformed, the genes inserted and the regeneration of genetically engineered conifer trees. We cover both Biolistic® and Agrobacterium-mediated transformation, and we detail transformation events with and without plant regeneration. We show that almost all conifer transformation work uses nptII as a selective marker, and very often uidA is included as a reporter gene. Further, we show that a range of genes that are of commercial interest for forest tree plantations have been introduced, such as herbicide resistance, insect resistance and those related to wood properties. We briefly discuss the future for biotechnology in the context of socially acceptable enhanced plantation forestry and under consideration of benefits and risks.

Mots clés

  • Genetic engineering
  • conifers
  • plantation forestry
Accès libre

Engineering Forest Trees with Heavy Metal Resistance Genes

Publié en ligne: 19 Oct 2017
Pages: 263 - 268

Résumé

Abstract

Pollution of soil and water with heavy metals such as mercury, cadmium and arsenic, is a worldwide problem. Phytoremediation, the use of plants to remove, sequester or detoxify pollutants, including heavy metals, offers an environmentally-friendly alternative to engineering- based methods for remediation. Forest trees have multiple features that make them particularly useful for removal of toxic heavy metals, especially if they can be engineered with genes allowing them to handle high levels of these elements. Although still in its infancy, research with transgenic trees carrying genes allowing them to detoxify or sequester some heavy metals has already made promising progress. Most of the work to date has been performed using poplar species and hybrids, although other woody species could be equally as useful. Trees have been engineered with genes for the handling of mercury, cadmium, copper and arsenic following two main approaches, phytoextraction and phytotransformation/ phytovolatilizaton. In vitro studies have shown the transgenic trees to have enhanced abilities to tolerate and/or accumulate these metals, and preliminary results from field tests indicate that the trees are functioning. New combinations of genes involved in metal transport or conversion may further enhance the heavy metal remediation capabilities of the transgenic trees. Given the environmentally friendly application, forest trees engineered for phytoremediation may be some of the first transgenic forest trees approved for operational deployment.

Mots clés

  • phytoremediation
  • gene transfer
  • heavy metals
  • pollution
  • hardwood trees
  • genetic engineering
  • transgenic tree
  • bioremediation
  • poplar
  • willow
Accès libre

Reduction of Lignin Content by Suppression of Expression of the LIM Domain Transcription Factor in Eucalyptus camaldulensis

Publié en ligne: 19 Oct 2017
Pages: 269 - 277

Résumé

Abstract

We report a reduction of lignin content in the woody plant Eucalyptus camaldulensis by the suppression of gene expression of the LIM domain transcription factor. Previously, we identified a cDNA encoding the tobacco (Nicotiana tabacum) LIM domain transcription factor, Nt1iml, involved in lignin biosynthesis and that specifically binds to an important cis-acting element, the PALbox sequence. The orthologous Eucalyptus gene of Ntliml, namely Ecliml, was isolated from the E. camaldulensis cDNA library (84% amino acid identity). The antisense Ntliml construct with a kanamycin-resistant gene was introduced into E. camaldulensis. The transgenic Eucalyptus plants grown in the greenhouse showed decreased expression levels of severallignin biosynthesis genes, phenylalanine ammonialyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-hydroxycinnamate CoA ligase (4CL). The abnormal phenotypic changes and a 29% reduction of lignin content were observed in the line LG12, in which the transcript level of Ecliml was most1y suppressed. Ec1iml is one of the key transcription factors involved in lignin biosynthesis.

Mots clés

  • Eucalyptus camaldulensis
  • Ecliml gene
  • transgenic Eucalyptus
  • lignin
  • holocellulose
Accès libre

The Overexpression of Glutamine Synthetase in Transgenic Poplar: A Review

Publié en ligne: 19 Oct 2017
Pages: 278 - 284

Résumé

Abstract

In investigating the pivotal role of glutamine synthetase in woody plant development, we have strived to develop an understanding of the biochemical and physiological mechanisms whereby enhanced expression of glutamine synthetase (GS) in poplar contributes to vegetative growth through enhanced nitrogen use efficiency. Considerable effort has also centered on characterization of enhanced resistance of transgenic GS overexpressor lines to abiotic stresses and proposed mechanisms. This summary of our work also focuses on future applications in forest tree improvement.

Mots clés

  • poplar
  • nitrogen assimilation
  • glutamine synthetase
  • genetic engineering
  • water stress tolerance
  • anthranilate synthase
Accès libre

Faster Evaluation of Induced Floral Sterilit

Publié en ligne: 19 Oct 2017
Pages: 285 - 291

Résumé

Abstract

A major concern over the use of transgenic trees is the potential for transgene dispersal through pollen and seeds. The incorporation of sterility inducing genes into transgenic lines of trees has been proposed to reduce or even avoid gene flow of transgenes into non-transgenic interbreeding species. The evaluation of strategies for the induction of sterility in transgenic forest tree species has been hindered by their long vegetative phases. In this study an early flowering 35S::Leafy poplar line was used for the faster evaluation of the sterility construct C-GPDHC::Vst1. The combination of two transgenic approaches, one to induce early flowering and a second for the induction of sterility, allowed evaluation of this sterility strategy two years after transformation. This is a very short period of time considering the long vegetative period of seven to twenty years common in forest tree species. This approach opens opportunities for the assessment of sterility mechanisms for this plant group.

Mots clés

  • sterility
  • biosafety
  • genetic engineering
  • transgenic trees
  • Populus
  • leafy
  • stilbene synthase
  • early flowering
37 Articles
Accès libre

Application of ISSR Markers to Fingerprinting of Elite Cultivars (Varieties/Clones) From Different Sections of the Genus Populus L.

Publié en ligne: 19 Oct 2017
Pages: 1 - 6

Résumé

Abstract

The Inter-Simple Sequence Repeat (ISSR) was used in this study for genetic fingerprinting and identification of 28 important Populus L. (poplar) cultivars (varieties/ clones), and determination of the genetic relationships among these cultivars. These 28 cultivars belonged to sections Aigeiros, Tacahamaca, Leuce, Turanga, and hybrids between sections Aigeiros and Tacahamaca. Out of 27 ISSR primers tested, eight primers generated clear multiplex profiles. The best three primers produced 154 easily detectable fragments, 129 (84%) of which were polymorphic among the cultivars. Each of these 3 primers produced fingerprint profiles unique to each of the accessions studied, and thus could be solely used for their identification. Twenty-five markers, unique to 10 of the cultivars studied, were detected. These markers may be converted into cultivar-specific probes for identification purposes. Genetic relationships among the cultivars were evaluated by generating a similarity matrix based on the simple matching coefficient and the unweighted pair group method with arithmetic average (UPGMA) dendrogram. The results showed a clear-cut separation of cultivars among different sections of poplar, and were in agreement with the genealogy of the sampled cultivars. The present study shows that ISSR markers could generate abundant polymorphism, are reproducible, and are quick for characterization of poplar cultivars. In the future, the markers used in this study, in combination with other molecular techniques, could provide a useful panel of ISSR markers for largescale DNA fingerprinting of poplar cultivars and determination of the genetic relationships among these cultivars.

Mots clés

  • Poplar
  • ISSR
  • Cultivars identification
  • Genetic relationships
Accès libre

Genetic Variation and Population Structure of Dendropanax morbifera Lev. (Araliaceae) in Korea

Publié en ligne: 19 Oct 2017
Pages: 7 - 13

Résumé

Abstract

Dendropanax morbifera Lev. (Araliaceae) is an economically important tree species because of its role in the production of golden varnishes as well as its use as an ornamental plant. As an endemic tree species of Korea, it is restricted to the southern parts of Korea as isolated populations. In this study, eight natural populations of D. morbifera were investigated by starch-gel electrophoresis in an attempt to determine the extent of its genetic diversity. Out of 8 natural populations, the Suak population in Jeju island showed the lowest level of genetic diversity, while the Wando island population in Jeonnam showed the highest level of genetic diversity. Levels of genetic diversity maintained in D. morbifera (A/L =1.5, P95 = 27.3%, Ho = 0.100, He = 0.095) were notably lower than those of other tree species with wider and more continuous geographic distributions. The reasons for the low level of genetic diversity in D. morbifera might be due to the genetic drift caused by artificial disturbances. Most of the total genetic diversity (96%) was found within the populations. The UPGMA dendrogram based on Nei’s genetic distance did not show any particular geographic patterns. The low level of genetic diversity suggested that there should be an urgent emphasis on the conservation study of this species.

Mots clés

  • Dendropanax morbifera
  • genetic variation
  • natural populations
  • isozymes
Accès libre

Comparison of Phenotype and Combined Index Selection at Optimal Breeding Population Size Considering Gain and Gene Diversity

Publié en ligne: 19 Oct 2017
Pages: 13 - 19

Résumé

Abstract

A breeding program was simulated in this study. Two alternative ways of selecting the breeding population for the following generation was compared. Phenotypic selection, which means to select just on the individual performance, and combined index selection, which means selection on predicted breeding value for each individual obtained by weighting family average and individual phenotype, were compared. The plant number (testing resource) and gene diversity (status number, Ns) were kept constant, but the breeding population size was variable and chosen for maximizing gain for the particular breeding scenario. At low and medium heritability phenotypic selection was inferior to combined index selection. Only when heritability was high phenotypic selection was as efficient (generation 1) as or more efficient (generation 5) than combined index selection. This contrasts to earlier studies done under constant breeding population size, where selection methods appeared similar. The advantage in gain of combined index selection is usually at a larger breeding population size. At limited heritability and breeding population size the difference is considerable. When breeding population size was kept rather small (<100), and the heritability limited, combined index selection can result in slightly higher gain than phenotypic selection at the same gene diversity, but this was at the cost of a much larger breeding population. Phenotypic selection and combined index selection appears as rather similar for many cases in this simple model used in this study. Considering other advantages with phenotypic selection, it may often be regarded as a competitive alternative.

Mots clés

  • heritability
  • genetic gain
  • status number
  • gene diversity
  • breeding population size
  • selection efficiency
Accès libre

Phenotypic Correlation and Path Coefficient Analysis of Nut Yield and Yield Components in Cashew (Anacardium occidentale L.)

Publié en ligne: 19 Oct 2017
Pages: 19 - 24

Résumé

Abstract

Relationships between cashew nut yield and nine agronomic traits comprising seven reproductive (nut and floral) and two vegetative characters were studied in 59 selected cashew genotypes over three production seasons. Phenotypic correlation analysis showed that nuts per panicle (r = 0.844), number of nuts per tree (r = 0.988) and number of hermaphrodite flowers per panicle (r = 0.863) were positively correlated with nut yield and could be used as primary components for improving yield. Although correlation analysis showed insignificant association between nut weight and nut yield, path analysis revealed that the trait had significant positive direct effect (0.317) on nut yield. The subtle indirect effects of nut weight and leaf size on nut yield were more important than their direct effects and could be classified as secondary components. Both the direct and indirect effects of weight of the whole fruit and tree canopy on nut yield were negative and appeared detrimental.

Mots clés

  • Anacardium occidentale
  • Correlation analysis
  • Path analysis
  • Breeding
Accès libre

Variation in Volume Production Through Clonal Deployment: Results From a Simulation Model to Minimize Risk for Both a Currently Known and Unknown Future Pest

Publié en ligne: 19 Oct 2017
Pages: 25 - 37

Résumé

Abstract

A simulation model was developed to examine optimum patterns of deploying selected clones in the hypothetical situations of both a currently known pest and an unknown future pest. We modelled the interactions between Sitka spruce (Picea sitchensis (Bong.) Carr.), an economically important forest tree in British Columbia and the northwestern U.S., and the spruce terminal weevil (Pissodes strobi (Peck)), a major pest in western spruces. The model is combined with the Province of British Columbia’s Tree and Stand Simulator (TASS) model to drive individual tree growth and stand establishment and development. Two clonal-sampling strategies are examined: a randomly drawn set of genotypes or clones, to depict the potential consequences of a new (e.g., exotic) or a previously unimportant natural pest attacking a ‘random’ set of genotypes, and a ‘fixed’ set of clones, emulating a ‘commercial’ or known set of clones for growth and resistance mechanisms. Simulations use a range of numbers of genotypes or clones (2, 6, 18 and 30), and three deployment patterns (a random mixture of ramets, single- clone blocks, and a mosaic of smaller clonal blocks), in one and five hectare (Ha) stands. Total merchantable timber volume on a per Ha basis at harvest age 80 is used to compare the various combinations and schemes. With both random and fixed chosen sets of clones, the random planting pattern (i.e., random mixture of ramets from the clonal set) produced the most volume. Eighteen randomly chosen clones generally produced more volume, than 2, 6 and 30 clones, but differences among 6, 18 and 30 clones were small in most cases, irrespective of planting pattern. For fixed clones, the use of more resistant clones with higher growth potential produced more volume; however, pure clonal blocks of the best clone were not better than a mixture of that clone and an inferior one. Reducing the effects of insect activity and attack on trees, by lowering the average annual temperature in the model, or turning off all insect ‘activity’, increased merchantable volume but did not change the optimum number of clones (~18) or deployment pattern (random mixture). Forestry agencies can weigh these findings against economic advantages of block plantings of similar genotypes, in the choice of an appropriate number of clones and a deployment strategy.

Mots clés

  • clonal forestry
  • genetic diversity
  • risk
  • merchantable volume loss
  • insect resistance
Accès libre

Genetic Variation of Common Ash (Fraxinus excelsior L.) Populations From Provenance Regions in Southern Germany by Using Nuclear and Chloroplast Microsatellites

Publié en ligne: 19 Oct 2017
Pages: 38 - 44

Résumé

Abstract

The genetic structure of 14 populations from three ash provenance regions (Fraxinus excelsior L.) in southern Germany (Aid Infodienst, 2003) is described by analysing the variation of four nuclear and five cpDNA microsatellites. The study of the nuclear microsatellites revealed high levels of genetic diversity but low levels of genetic differentiation, suggesting a high degree of gene flow among regions and/or human interference by introducing plant material coming from different provenances. The distributions of the allele frequencies and the genetic structures at these four microsatellite loci did not allow the identification of distinct provenance regions, although “private alleles” were encountered with moderate to low frequencies (above 5 percent). Specifically, the Rhine valley populations (provenance region 81105) and these from the Swabian Jura and Black Forest (provenance region 81107) revealed private alleles at the two microsatellite loci Femsatl4 and Femsatl12. A more distinct differentiation between provenances was found based on the cpDNA markers. Evidence on genetic delineation and characterization of ash provenances is discussed. Based on these results, provenance regions can be genetically characterised but further analysis of ash populations and of reproductive material (seeds or seedlings) would be of great importance for provenance delineation, as well as gene conservation and sustainable management of ash populations.

Mots clés

  • common ash
  • Fraxinus excelsior
  • genetic variation
  • microsatellites
  • genetic structure
  • differentiation of populations
Accès libre

Phylogenetic Relationship Within Genus Araucaria (Araucariaceae) Assessed by Means of AFLP Fingerprints

Publié en ligne: 19 Oct 2017
Pages: 45 - 52

Résumé

Abstract

Highly polymorphic AFLP markers were applied to analyse the phylogenetic relationships of seven species from three sections within genus Araucaria (Araucariaceae) with cladistic and phenetic approaches. The objectives of the study were to compare the intrageneric relationships within Araucaria assessed by AFLP markers with the classification according to chloroplast DNA sequences and morphological characters. The AMOVA revealed 48% of the variation among species. The results of the principal coordinate analysis revealed three distinct groups: (1) A. angustifolia and A. araucana (= section Araucaria), (2) A. bidwillii (= section Bunya) and (3) A. cunninghamii, A. heterophylla, A. rulei and A. scopulorum (= section Eutacta). In the cladistic and phenetic analyses, phylogenetic trees were subdivided into two sister clades, one comprising the samples from section Eutacta, the other one was divided again into two sister clades corresponding to sections Araucaria and Bunya. These results are congruent with a previous phylogenetic study of the family Araucariaceae based on rbcL sequences and with the classification of genus Araucaria based on morphological characters. Both rbcL sequence data and AFLP analyses do not support section Bunya as one of the oldest sections within genus Araucaria, as suggested by the fossil record. The utility of AFLP markers for phylogenetic analyses is discussed.

Mots clés

  • Araucaria
  • AFLP
  • phylogeny
  • phylogenetic relationships
Accès libre

Short Note: Crossability Between Pinus uliginosa and its Putative Parental Species Pinus sylvestris and Pinus mugo

Publié en ligne: 19 Oct 2017
Pages: 52 - 54

Résumé

Abstract

Results of artificial fertilization of P. uliginosa with P. sylvestris and P. mugo are presented and discussed. P. sylvestris and P. mugo are thought to be the parental species of P. uliginosa. Two grafts of one P. uliginosa clone from Arboretum of the Institute of Dendrology in Kórnik, Poland were used as mother individuals. One individual of P. sylvestris and one individual of P. mugo were the pollen donors. Three mature cones were obtained as the result of artificial pollination of P. uliginosa with P. mugo pollen. Out of 107 seeds, 68 were filled what gives 63%. P. uliginosa conelets pollinated with P. sylvestris pollen were all aborted. Based on obtained data, close phylogenetic relationship between P. uliginosa and P. mugo complex is suggested.

Mots clés

  • P. uliginosa
  • P. sylvestris
  • P. mugo
  • hybridization
  • pollination
  • crossability
Accès libre

DNA From Ancient Cedar Wood From King Midas’ Tomb, Turkey, and Al-Aksa Mosque, Israel

Publié en ligne: 19 Oct 2017
Pages: 54 - 62

Résumé

Abstract

Ancient Taurus cedar (Cedrus libani A. Rich) wood samples from the Tumulus of King Midas at the Gordion archaeological site (about 2700 years old), near Ankara, Turkey, and from the Al-Aksa Mosque (about 1500 to 1900 years old), Jerusalem, Israel, were characterized by studying the sequences of ribosomal DNA (rDNA) internal transcribed spacers (ITS1 and ITS2). After extraction of the DNA, the ITS regions were amplified utilizing the polymerase chain reaction, followed by sequencing, BLAST searches for similar sequences, and phylogenetic analyses. Fifty-six sequences were obtained. In BLAST searches of existing sequence databases, most were closest to those from humans and fungi. However, two sequences exhibited similarities with conifer ITS sequences. One was an ITS1 region from the Gordion wood specimen, and the other one was an ITS2 region from the Al-Aksa wood specimen. Phylogenetic analyses indicated that both were closest to Taurus cedar (C. libani, also known as Lebanon cedar) ITS sequences from three recent samples of Taurus cedar from two sites in Turkey. However, they exhibited many differences from the recent C. libani rDNA ITS sequences from Turkey, probably due to degradation of the DNA in the ancient samples. The implications of the results on future studies are discussed.

Mots clés

  • Ancient DNA
  • Midas
  • Gordion
  • Cedrus libani
  • wood
Accès libre

Stepwise Penalty Index Selection from Populations with a Hierarchical Structure

Publié en ligne: 19 Oct 2017
Pages: 62 - 70

Résumé

Abstract

By adding a penalty to a candidate’s breeding value for its relationship with the selected individuals, two indexes were constructed as criteria for stepwise selection of superior individuals from populations with a hierarchical structure. The relationship was expressed in terms of either family contribution or group coancestry. One of the indexes was derived from an optimal selection model. A stepwise procedure that screened superior individuals one by one was introduced to make selection based on these indexes possible. Two penalty selection methods exclusively maximized gain at given coancestry. Both methods produced all identical solutions in most of the populations simulated, and were nearly equivalent in the remaining populations, particularly when heritability was high and the population structure was simple. A better balance between gain and coancestry following penalty index selection can be obtained by avoiding the two extreme solutions: combined- index and within-family selection, and using simple mating designs rather than complex ones.

Mots clés

  • breeding value
  • penalty index
  • family contribution
  • gain
  • group coancestry
Accès libre

Accuracy of Ranking Individuals in Field Tests of Different Designs: A Computer Simulation

Publié en ligne: 19 Oct 2017
Pages: 70 - 77

Résumé

Abstract

A computer simulation was conducted to investigate the accuracy of ranking individual trees in field tests of different designs. A test population that consists of 900 trees from 45 full-sib families generated by three 6-parent disconnected half-diallels was considered. One incomplete block design with single-tree plots and four complete block designs with 1, 2, 4, and 10-tree row plots were examined. Various narrow-sense heritabilities, site variation patterns (patch sizes and gradient slopes), and two levels of dominant to additive genetic variance ratios (0 and 0.30) were evaluated. Results indicate that the accuracy of ranking depends more on the heritability of the trait and less on the magnitude of the dominant genetic variance, site variation patterns, and field designs. With patchy site variation, differences in ranking accuracy were observed for different designs, but became smaller with higher heritabilities. Impact of environmental gradient on the accuracy of individual ranking was negligible. Incomplete block design with single-tree plots (ICB1) provided the most accurate ranking when heritability was low while complete block design with 2-tree plots (RCB2) appeared to be the best when heritability was high. Large row plot designs were among the least effective in all the simulated scenarios. For traits with medium heritabilities, the statistical efficiencies of ICB1 and RCB with 1 and 2-tree plots are comparable.

Mots clés

  • breeding value
  • progeny testing
  • field design
  • ranking accuracy
  • computer simulation
Accès libre

Genetic Parameters and Strategies for Genetic Improvement of Stiffness in Radiata Pine

Publié en ligne: 19 Oct 2017
Pages: 77 - 84

Résumé

Abstract

The two main objectives of this study were: (1) to determine how early is it possible to undertake selection to improve the stiffness of corewood; (2) to determine if the selection based on corewood stiffness could also improve outerwood stiffness, and vice versa. Breastheight data from two progeny trials of Pinus radiata D. Don were used. In the first trial (age 30 years), data on Silviscan predicted stiffness (MoE) was obtained for each growth ring on each core sample from 50 open-pollinated families. In the second trial (age 14 years), data on static-bending MoE was obtained using clearwood sticks (300 × 20 × 20 mm) cut from each tree from 18 control-pollinated families. MoE varied from 3.5 GPa in rings 1-5 to about 17 GPa in rings 21-25. Coefficients of variation of corewood and outerwood MoE were about 20-30% and 15-20% respectively. Estimates of narrowsense heritability for MoE were generally higher (0.50-0.70) in the corewood compared with the outerwood (0.15-0.30). Early selection for MoE could yield substantial gain in corewood MoE but only small gains, if any, in outerwood MoE (especially for rings 21-30). Estimated genetic correlations between density and stiffness appeared moderate in the corewood zone, but high in the outerwood zone. Selection based on density (using 5-mm cores) and acoustic stiffness (using standing tree tools), assessed at age 6-7 years, appeared to be a good option to improve both corewood and outerwood stiffness.

Mots clés

  • Stiffness
  • sound velocity
  • wood density
  • heritability
  • breeding strategy
  • genetic correlation
  • age-age correlation
  • early selection
  • Pinus radiata
Accès libre

Estimating Genetic Parameters for Wood Density of Scots Pine (Pinus sylvestris L.)

Publié en ligne: 19 Oct 2017
Pages: 84 - 92

Résumé

Abstract

Wood density was analysed and annual ring width was measured on increment cores from 1400 trees in a 30-year-old full-sib progeny test of Scots pine (Pinus sylvestris L.) in north Sweden. Genetic parameters for wood density were analysed separately for ten outer annual rings, and for simple averages of the five most recent years. The evaluation included genetic correlations with height and stem diameter. Heritabilities of density estimated separately for each annual ring was 0.14-0.26 without any age trend, and jointly for the ten or five latest rings 0.30-0.33; for height growth it was 0.30-0.42 and for stem diameter 0.11-0.13. Additive genetic correlations with height and stem diameter were negative with the simplest statistical model (ȓA = -0.425 and 0.511, respectively) but vanished or diminished when ring width was added as covariate. Density breeding values calculated for the parent trees for each of ten annual rings separately varied considerably between parent trees and between years, tending to increase with increasing age, with a substantial increase between the ages 14 to 16 years from the pith. This age fits well with literature data on the change from juvenile to mature wood. The genetic correlation for wood density between rings from different years was high: ȓA = 0.8 ten years apart, increasing to 1.0 for neighbouring rings. The high genetic correlations for wood density between the innermost and outermost annual rings indicate possible strong covariation between juvenile and/or transition wood and mature wood. The annual variation in wood density in relation to genetic regulation, phenology, environmental conditions, and development from juvenile to mature age is discussed.

Mots clés

  • annual ring density
  • annual ring width
  • breeding value
  • genetic correlation
  • heritability
  • juvenile wood
  • mature wood
  • multitrait REML
  • repeated-measurement model
  • wood density
Accès libre

Cytogenetic Effect of Radiation in Seed of Oak (Quercus robur L.) Trees Growing on Sites Contaminated by Chernobyl Fallout

Publié en ligne: 19 Oct 2017
Pages: 93 - 101

Résumé

Abstract

The Chernobyl accident was one of the largest man made environmental disasters and had significant consequences for people, animal and plants, particularly on land contaminated by radionuclides. Common oak (Quercus robur L.) is the main forest species on land contaminated by Chernobyl fallout areas in the Voronezh region. Therefore it is very important to know how irradiation of oak trees will affect the quality of oak progeny in future consequently. Cytogenetic characteristics such as mitotic activity, level and spectrum of mitotic disturbances, frequency of the cells with persistent nucleoli in the stages of metaphase, anaphase, telophase and multinuclei in interphase cells were investigated in progeny of common oak (Quercus robur L.) trees subjected to different degrees of radioactive contamination. In progeny growing under the influence of this radioactive contamination we observed variability of such cytogenetic characteristics as mitotic activity. However, the variability of this trait was also connected to fluctuations in the weather. The duration of mitotic stages (which may be connected with disturbance of spindle division formation and absence of cytotomy) also varied. An increase in chromosomal bridges among other types of mitotic abnormalities may be considered a result of increases in the meristematic cells repair activities. Activity of some dormant nucleolus organizer regions was also observed. The level of pathological mitoses increased in particular years and was decreased in others. Thus irradiation induces instability of cytogenetic characteristics in oak progeny that produces a type of “wave kinetics” in the mutation rate. This makes them more sensitive to environmental conditions. Therefore we do not recommend to use the oak seeds collected from irradiated areas for reforestation because undesirable genetic changes may have occurred in them.

Mots clés

  • Quercus robur L. (common oak)
  • mitotic activity
  • mitotic disturbances (mitotic pathology)
  • nucleolus
  • radioactive irradiation
  • Chernobyl Accident
Accès libre

Identification of Atractylodes japonica and A. macrocephala by RAPD analysis and SCAR Markers

Publié en ligne: 19 Oct 2017
Pages: 101 - 105

Résumé

Abstract

The Chinese plant, “Packchul”, (Atractylodes japonica or A. macrocephala), is a very important Chinese medicinal herb plant and is called Sabju in Korea. The levels of the active components are different between these two species, but these medicines are sold in Korean herbal markets without discrimination. This study was carried out to develop a method that could be used to discriminate between A. japonica and A. macrocephala based on molecular markers. To discriminate between A. japonica and A. macrocephala, RAPD analyses were used to develop SCAR markers. Eighteen species-specific RAPD bands were obtained from 52 OPERON and URP primer sets. Two SCAR markers were developed from these RAPD clones. Both SCAR markers were cloned into pGEM-T-Easy vectors and then subjected to nucleotide sequence analysis and designated AjR1 (1,117 bp) and AmR1 (1,325 bp). These two markers were sufficient to discriminate between samples of A. japonica and A. macrocephala.

Mots clés

  • Atractylodes japonica
  • A. macrocephala
  • RAPD
  • SCAR
Accès libre

Genetic Diversity of Two Evergreen Oaks [Quercus suber (L.) and Quercus ilex subsp. rotundifolia (Lam.)] in Portugal using AFLP Markers

Publié en ligne: 19 Oct 2017
Pages: 105 - 118

Résumé

Abstract

The genetic variability of cork oak (Quercus suber, L.) in Portugal was evaluated by AFLP using five primer combinations. Three hundred and thirteen trees from three geographically contrasting regions exhibited a high level of genetic variation. The genetic profile of each individual is composed of 291 loci, randomly positioned in the genome and consists of monomorphic and polymorphic fragments. Similarities and dissimilarities among the individuals were quantitatively evaluated by numerical taxonomy. The overall sample shows a proportion of AFLP polymorphic markers of 71%, denoting a high level of variability. Ninety percent of the polymorphic markers identified in cork oak genotypes are uniformly distributed throughout the cork oak populations of Algarve, Alentejo and Trás-os-Montes regions. The coefficients of genetic similarity vary from 0.61 to 0.88 implying that 60% of fragments found are common. A sample of 52 holm oak [Quercus ilex subsp. rotundifolia (Lam.)] trees from overlapping areas was also analysed by AFLP with the same five primer combinations. However the codification of markers together with those selected on cork oak profiles was feasible with only one primer combination due to an apparent much higher polymorphism. AFLP and numerical taxonomy analysis enabled to differentiate the taxa and showed that the level of similarity observed between the profiles of the individuals from holm oak species was lower than that observed in cork oak, implying that apparently the degree of polymorphism is higher in Q. ilex subsp. rotundifolia than that quantified in Q. suber. A Bayesian approach was used to assess Q. suber total genetic diversity (Ht = 0.2534, P < 0.001) of which 1.7% (Fst = 0.0172, P < 0.001) was assigned to differences among populations. Analysis of molecular variance (AMOVA) showed that most genetic variation is comprised within populations (96%) while 3.6% is among populations (Φst = 0.036, P < 0.001). Differences among populations within geographic regions account for 2.6% (Φsc = 0.026, P < 0.001) of the total variation and only 1.3% (Φct = 0.013, P = 0.007) is attributed to variation among regions denoting little differentiation of populations over a range of 700 km.

Mots clés

  • AFLP
  • genetic diversity
  • genetic introgression
  • Quercus suber (L.)
  • Quercus ilex subsp. rotundifolia (Lam.)
Accès libre

Identification of Species-Diagnostic ISSR Markers for Six Eucalyptus Species

Publié en ligne: 19 Oct 2017
Pages: 119 - 122

Résumé

Abstract

Eucalyptus is planted worldwide for raw material in paper and rayon industry. It is a potential out-crosser and the natural populations are highly heterogeneous displaying strong inbreeding depression. Eucalyptus hybrids have been intensively utilized for their vigor, higher wood quality and resistance to diseases. Identification of species for hybridization is predominantly based on morphological characters and is not always reliable. Hence, DNA marker based species identification and hybrid validation is an important and efficient tool in breeding programs. In the present study, attempts were made to identify species - diagnostic markers for six eucalypt species (E. camaldulensis Dehnh, E. citriodora Hook, E. grandis W. Hill ex Maiden, E. pellita F. Muell, E. tereticornis Sm and E. urophylla S.T. Blake) using ISSR-PCR fingerprints. PCR amplification using seven ISSR primers resulted in significant polymorphism among the population from different species. E. citriodora and E. tereticornis showed monomorphic frequency of maximum 37.5% and minimum 14.3% respectively. Twenty species-diagnostic markers were identified for E. camaldulensis, E. citriodora, E. grandis and E. urophylla while no marker was detected for E. pellita and E. tereticornis. A maximum of eleven and a minimum of one species-diagnostic marker were recorded for E. citriodora and E. camaldulensis respectively. Among the twenty markers, nine were present in all the individuals of a particular species.

Mots clés

  • DNA
  • Inter-Simple-Sequence-Repeat markers
  • Eucalypt
  • Fingerprinting
  • Tree breeding
Accès libre

Identification of European and Japanese Larch and Their Interspecific Hybrid with Morphological Markers: Application to Young Seedlings

Publié en ligne: 19 Oct 2017
Pages: 123 - 134

Résumé

Abstract

Open-pollinated hybridisation seed orchards of European and Japanese larches produce mixed progenies combining a highly variable proportion of hybrids along with pure parental species. For several reasons, it is desirable to identify and to sort out hybrids from pure species at the seedling stage. Taxa identification of 1-2 yr-old seedlings was attempted using non-destructive assessment of several traits, including morphology, phenology, growth and architecture parameters. Two sets of progenies originating from 10 open-pollinated hybridisation seed orchards were used, relying in a first step on taxa identification of individual seedlings with diagnostic molecular markers. Based on 21 traits assessed, some clear trends in pure species and hybrid features were apparent but due to the large and overlapping ranges of taxa characteristics, no single parameter allowed unambiguous identification of taxa. Combination of traits through linear discriminant analysis made possible correct classification of 90.2% to 98.6% of individuals depending on the orchard although there were a few problematic orchards. Two traits appeared particularly pertinent for discriminating young plants taxa, namely 1st-yr leaf retention (marcescence) and the bark colour of 2nd-year shoot increments. Results were corroborated using progenies from several orchards and over two experimental periods.

Mots clés

  • Larix
  • taxonomy
  • hybrid
  • seedling
  • morphology
  • phenology
  • growth
  • linear discriminant analysis
  • seed orchard
Accès libre

Early Selection of Douglas-Fir across South Central Coastal Oregon, USA

Publié en ligne: 19 Oct 2017
Pages: 135 - 141

Résumé

Abstract

Details are given of three first-generation progeny tests (CB1, CB2 and CB3) of coastal Douglas-fir (Pseudotsuga menziesii [MIRB.] FRANCO var. menziesii) planted in the Coos Bay region of south-central coastal Oregon in 1973. The three tests included 15 polymix families based on a 10-pollen mix, and 27 families openpollinated on the ortet. The present study gives heritabilities and additive genetic correlations for growth measured between two and 17 years after planting. Correlated responses are estimated for volume at 17 years from early selection for height and diameter. Between four and 17 years after planting the individual heritability (h2) of height of coastal Douglas-fir across the Coos Bay tests was quite stable between h2 = 0.18 and 0.22. The heritability of stem diameter age-forage was consistently much lower than for height. In the critical age range for early selection between five and 10 years the individual heritability of diameter ranged from h2 = 0.07 to 0.10. The additive genetic correlations involving volume-17 and height or diameter increased to high values of rA = 0.80 to 0.84 between eight to 10 years after planting. Before seven years the absolute values of juvenilemature correlations were much lower. The higher heritability of height made this trait the best criterion for early indirect selection to improve mature stem volume growth. Across these Coos Bay tests, early selection on stem height measured at 5-8 years after planting was estimated to produce almost 40% more gain per year in volume-17 compared with direct selection at 17 years on volume-17 itself. The recommendation for maximizing gain per year in mature volume of coastal Douglas-fir at Coos Bay is to select on height at 7-8 years when the mean height of trees in tests should be around 4.5 to 5.5 meters.

Mots clés

  • Douglas-fir
  • growth
  • heritability
  • juvenile-mature correlation
  • early selection efficiency
Accès libre

Bud Removal Affects Shoot, Root, and Callus Development of Hardwood Populus Cuttings

Publié en ligne: 19 Oct 2017
Pages: 141 - 148

Résumé

Abstract

The inadvertent removal and/or damage of buds during processing and planting of hardwood poplar (Populus spp.) cuttings are a concern because of their potential impact on shoot and root development during establishment. The objective of the current study was to test for differences in shoot dry mass, root dry mass, number of roots, length of the longest root, and callus dry mass among ten poplar clones subjected to three pre-planting bud removal intensities (0%, 50%, 100%). The ten clones and their genomic groups were: DM115 (P. deltoides Bartr. ex Marsh× P. maximowiczii A. Henry); DN34, I45-51 (P. deltoides× P. nigra L.); NC13446, NC13563, NC13649, NC13685, NC13747 [(P. trichocarpa Torr. & Gray× P. deltoides)× P. deltoides]; and NM2, NM6 (P. nigra× P. maximowiczii). Cuttings, 20 cm long, were processed from shoots collected January 2005 from stool beds established at Hugo Sauer Nursery in Rhinelander, Wisconsin, U.S.A. (45.6 °N, 89.4°W). We measured the traits from harvested cuttings after 14 d of growth. The treatment× clone interaction governed shoot dry mass (P < 0.0001). In general, the top four clones (DM115, DN34, NM2, NM6) exhibited the best shoot dry mass with 0% and 50% of buds removed, while differences among treatments for the remaining clones were negligible. Clones differed for root dry mass (P < 0.0001), while the treatment and clone main effects governed number of roots (P = 0.0126, P < 0.0001, respectively) and length of the longest root (P = 0.0077, P < 0.0001, respectively). Cuttings subjected to the 0% treatment exhibited the greatest number of roots, while cuttings of the 0% and 50% treatment exhibited the greatest length of the longest root. The treatment× clone interaction governed the presence of callus (P = 0.0161), while clones differed for callus dry mass (P < 0.0001). Bud removal did not affect root biomass but it did impact root initiation. Unlike shoot dry mass, the response to removing buds for all rooting traits was not clone-specific. From a practical standpoint, inadvertently damaging and/or removing ≤ 50% of the buds during processing and planting should not be a concern for establishment.

Mots clés

  • adventitious rooting
  • hybrid poplar
  • preplanting treatment
  • vegetative propagation
  • Populus deltoides
  • P. nigra
  • P. maximowiczii
  • P. trichocarpa
Accès libre

Phenology and Control Pollination Studies in Casuarina equisetifolia Forst

Publié en ligne: 19 Oct 2017
Pages: 149 - 155

Résumé

Abstract

Studies on phenology, floral biology and seed production were conducted in two provenance trials and a clonal hedge orchard of C. equisetifolia. Observations in seventeen populations indicate that predominant dioecy with low proportion of monoecy as the commonest sexual strategy. Flowering occurs twice in a year coinciding with the South West and North East monsoons. C. equisetifolia exhibits strong anemophilous adaptations such as very high pollen output, reduced flowers with large stigmatic area and light weighing winged fruits. Pollen is viable up to 99%, storable in 4°C up to three months with no loss in fertility. Trees start reproducing within two years of planting. Local land races produce ten to twenty times higher seeds than the recent introduced natural provenances and exotic landraces. Controlled pollination resulted in lower seed set than observed in open pollination. Selfing leads to normal seed set in monoecious trees. Inter specific cross with C. junguhuhniana pollen parent results in viable progeny.

Mots clés

  • Anemophily
  • Casuarina
  • cone
  • landrace
  • phenology
  • provenance
  • pollination
  • reproduction
  • seed
Accès libre

Segregation and Linkage Relationships of Allozymes in Pinus Brutia Ten

Publié en ligne: 19 Oct 2017
Pages: 155 - 160

Résumé

Abstract

Female gametophytes of Pinus brutia Ten. were analyzed to study Mendelian segregation and linkage among allozyme loci in a seed orchard composed of 28 clones. Isozyme variants of nine enzyme systems encoding 14 loci from megagametophytes were assayed by starch gel electrophoresis. While six of the 14 loci were monomorphic, the remaining eight were polymorphic. Analysis of observed segregation ratios of all polymorphic loci except for Sdh1, showed a good fit to the 1:1 ratios expected for Mendelian inheritance. Linkage relationships of the eight polymorphic allozyme loci were analyzed by testing 23 of the 28 possible two-locus combinations. Two-locus segregations in three pairs (Got2- Mdh1, Got2-Pgi2 and Pgd3-Sdh1) were significantly heterogeneous (P ≤ 0.05). Relatively weak linkage was observed between only one pair of genes (Adh2:Got2). Recombination fraction for Adh2:Got2 was found to be 0.24 (± 0.06).

Mots clés

  • linkage
  • allozyme
  • inheritance
  • seed orchard
  • Pinus brutia
Accès libre

Genetic Diversity and Gene Flow of Quercus crispula in a Semi-Fragmented Forest Together With Neighboring Forests

Publié en ligne: 19 Oct 2017
Pages: 160 - 169

Résumé

Abstract

The genetic diversity and differentiation in Quercus crispula populations in the Chichibu Mountains, central Japan, were evaluated using six microsatellite markers. Gene flow into a 2500-m2 semi-fragment of a natural forest from the neighboring natural forest at a distance of more than 50m was also evaluated using parentage analysis. All five populations in the mountains had similar levels of genetic diversity (He = 0.752-0.792), and the level of population differentiation was low (FST = 0.016). The semi-fragmented stand showed similar genetic diversity with the neighboring unfragmented forests, and Hardy-Weinberg disequilibrium was not found (FIS = 0.083 in adults, 0.025 in seedlings). In the semifragment, 70 seedlings were examined; according to the parentage analysis, eight of the 70 seedlings (ca. 11%) had neither of the parent trees in this fragment. These seeds must have been transported from a distance of more than 50 m; therefore, there could be a possibility that the seeds were dispersed by birds. A similar trend of seed flow into the fragment was also confirmed by genotyping endocarps of hypogeal cotyledons, while more frequent seed flow was found in the neighboring unfragmented forest. Of the remaining 62 seedlings, the maternal trees (but not the paternal trees) of 29 seedlings and both parent trees of 33 seedlings were detected in the semi-fragment. These results indicate that the gene flow among the populations occurs frequently via pollen dispersal and occasionally via seed dispersal and that, at least the current levels of genetic diversity have been maintained in such fragmented forests.

Mots clés

  • forest fragmentation
  • microsatellites
  • parentage analysis
  • Quercus crispula
Accès libre

Date of Shoot Collection, Genotype, and Original Shoot Position Affect Early Rooting of Dormant Hardwood Cuttings of Populus

Publié en ligne: 19 Oct 2017
Pages: 169 - 182

Résumé

Abstract

Identifying superior combinations among date of dormant- season shoot collection, genotype, and original shoot position can increase the rooting potential of Populus cuttings. Thus, the objectives of our study were to: 1) evaluate variation among clones in early rooting from hardwood cuttings processed every three weeks from shoots collected throughout the dormant season and 2) evaluate variation among genomic groups in early rooting of the same cuttings while testing for differences among three parental shoot positions (apical, middle, basal). We tested 22 clones belonging to six genomic groups ([P. trichocarpa Torr. & Gray × P. deltoides Bartr. ex Marsh] × P. deltoides ‘BC’, P. deltoides ‘D’, P. deltoides × P. maximowiczii A. Henry ‘DM’, P. deltoides × P. nigra L. ‘DN’, P. nigra × P. maximowiczii ‘NM’, P. trichocarpa ‘T’). Cuttings, 20 cm long, were processed from shoots collected every three weeks beginning 1 Dec. 2003 until 9 Apr. 2004 from stool beds established at Hugo Sauer Nursery in Rhinelander, Wisconsin, USA (45.6 °N, 89.4°W). We measured number of roots and root dry weight from harvested cuttings after 14 days of growth. The interaction between date of shoot collection and clone governed both traits (P < 0.0001). In general, clones exhibited the best rooting when cuttings were processed from shoots collected on or after 23 Feb. 2004. The interaction between date of shoot collection, genomic group, and shoot position governed number of roots (P = 0.0348) and root dry weight (P = 0.0262). There was broad variation in number of roots and root dry weight of apical, middle, and basal cuttings within and among genomic groups across dates of shoot collection, with 15 Mar. 2004 being an important date because differences among positions began to develop or changed relative to earlier dates. Thus, for increased plantation establishment potential with similar genotypes, we recommend collecting stool shoots no sooner than the end of February and matching cuttings of specific shoot positions to each genomic group.

Mots clés

  • Populus genomic groups
  • hybrid poplar
  • adventitious rooting
  • genotype x environment interaction
  • whip
  • stool bed
Accès libre

Early Selection of Radiata Pine

Publié en ligne: 19 Oct 2017
Pages: 182 - 191

Résumé

Abstract

Additive genetic, dominance genetic and phenotypic variances and corresponding correlations were estimated for growth data collected from disconnected half-diallel progeny trials involving 25 Pinus radiata D. DON parents and replicated across two sites in central North Island, New Zealand. Sectional area of stem was measured at three, seven, 10 and 13 years after planting at both sites, and height at three and 10 years at one site. Sectional area at three years exhibited similar levels of estimated additive (σA2) and dominance (σD2) genetic variance. However, levels of σD2 remained approximately constant between three and 13 years while σA2 increased substantially. Thus, sectional-area growth changed from being under equal additive and dominance genetic control at three years to almost complete additive genetic control from seven to 13 years. The greater increase in additive variance relative to phenotypic variance led to increases in individual heritability from 0.16 to 0.28 to 0.35 for sectional-area increments between 3-7, 7-10 and 10-13 years, respectively. Height growth exhibited negligible levels of σD2 for the three- and 10-year measurements. The early sectional-area increment between 3-7 years showed an estimated additive genetic correlation of 0.87 with “mature” sectional area at 13 years. Subsequent sectional-area increments between 7-10 and 10-13 years showed estimates of additive genetic correlations of 0.99 with sectional area at 13 years. Dominance genetic correlations were much lower in magnitude, reflecting inconsistent dominance effects over time.

Mots clés

  • Pinus radiata
  • additive variation
  • dominance variation
  • juvenile-mature correlation
  • heritability
Accès libre

Comparison Between Open Pollinated Progenies and Hybrids Performance in Eucalyptus grandis and Eucalyptus urophylla

Publié en ligne: 19 Oct 2017
Pages: 192 - 196

Résumé

Mots clés

  • reciprocal recurrent selection
  • half-sib progenies
  • full-sib progenies
  • wood basic density
  • genetic correlation
  • genetic variance
  • heterosis
  • Eucalyptus
Accès libre

Genetic Variability and Structure of The Wild Service Tree (Sorbus torminalis (L.) Crantz) in Poland

Publié en ligne: 19 Oct 2017
Pages: 197 - 202

Résumé

Abstract

Sorbus torminalis is a rare forest tree species in Poland. Allelic and genotypic structures at 25 isozyme gene loci were observed in 20 populations from Poland, situated mainly along a latitudinal gradient. Levels of genetic diversity were high both at the species level (P = 44%, He = 0.435) and within populations (mean P = 40.8%, mean He = 0.373). Levels of differentiation among populations were relatively high (FST = 0.17) and a noticeable geographic structure of this differentiation was detected. The population in the ‘Brekinia’ reserve had a unique genetic structure of a clonal population and was the most distinct from the other populations.

Mots clés

  • electrophoresis
  • isozymes
  • genetic diversity
  • population differentiation
  • Sorbus torminalis
Accès libre

Parental and Consensus Linkage Maps of Eucalyptus globulus Using AFLP and Microsatellite Markers

Publié en ligne: 19 Oct 2017
Pages: 202 - 217

Résumé

Abstract

Parental and consensus maps were constructed in an F2 inter-provenance cross of Eucalyptus globulus, using amplified fragment length polymorphism (AFLP) and microsatellite (or simple sequence repeats [SSR]) markers. The female map had 12 linkage groups and 118 markers, comprising 33 SSR and 85 AFLP loci. The male map had 14 linkage groups and 130 markers comprising 36 SSR and 94 AFLP loci. The integrated map featured 10 linkage groups and 165 markers, including 33 SSR and 132 AFLP loci, a small 11th group was identified in the male parent. Moderate segregation distortion was detected, concentrated in gender specific groups. The strongest distortion was detected in the female parent for which causal mechanisms are discussed. The inclusion of SSR markers previously mapped in several different eucalypt species within the subgenus Symphyomyrtus (E. globulus, E. camaldulensis, and predominantly E. grandis and E. urophylla), allowed comparison of linkage groups across species and demonstrated that linkage orders previously reported in E. globulus, E. grandis and E. urophylla were largely conserved.

Mots clés

  • Linkage map
  • Eucalyptus globulus
  • SSR
  • AFLP
  • comparative mapping
Accès libre

Genetic Variation and Correlations between Growth and Wood Density of Calycophyllum spruceanum at an Early Age in the Peruvian Amazon

Publié en ligne: 19 Oct 2017
Pages: 217 - 228

Résumé

Abstract

Calycophyllum spruceanum (Benth.) Hook. f. ex K. Shum. is an important timber-tree species in the Peruvian Amazon Basin. As farmers and industry often use wood from young trees, it is important to investigate variation in juvenile wood properties in this species. A provenance/progeny test was established to evaluate genetic variation in growth and wood properties of young trees, the strength of their genetic control as well as their interrelationships both at the genetic and the phenotypic level in different planting zones. In this paper, results are presented for tree height and stem diameter (near ground level) at 16, 28 and 39 months; and stem diameter and basic density of the wood at breast height at 39 months. Significant variation due to provenances and especially due to families within provenances was found in growth and wood density. Phenotypic and genetic correlations indicated that larger trees tended to have denser wood. Wood density had higher heritability than height and diameter; and genetic control over height, diameter and density was generally highest in the planting zone where trees grew most rapidly.

Mots clés

  • provenance
  • family
  • environment
  • heritability
  • phenotypic and genetic correlations
  • juvenile wood
Accès libre

Construction of Microsatellite Linkage Maps for Corymbia

Publié en ligne: 19 Oct 2017
Pages: 228 - 238

Résumé

Abstract

The genus Corymbia is closely related to the genus Eucalyptus, and like Eucalyptus contains tree species that are important for sub-tropical forestry. Corymbia’s close relationship with Eucalyptus suggests genetic studies in Corymbia should benefit from transfer of genetic information from its more intensively studied relatives. Here we report a genetic map for Corymbia spp. based on microsatellite markers identified de novo in Corymbia sp or transferred from Eucalyptus. A framework consensus map was generated from an outbred F2 population (n = 90) created by crossing two unrelated Corymbia torelliana × C. citriodora subsp. variegata F1 trees. The map had a total length of 367 cM (Kosambi) and was composed of 46 microsatellite markers distributed across 13 linkage groups (LOD 3). A high proportion of Eucalyptus microsatellites (90%) transferred to Corymbia. Comparative analysis between the Corymbia map and a published Eucalyptus map identified eight homeologous linkage groups in Corymbia with 13 markers mapping on one or both maps. Further comparative analysis was limited by low power to detect linkage due to low genome coverage in Corymbia, however, there was no convincing evidence for chromosomal structural differences because instances of non-synteny were associated with large distances on the Eucalyptus map. Segregation distortion was primarily restricted to a single linkage group and due to a deficit of hybrid genotypes, suggesting that hybrid inviability was one factor shaping the genetic composition of the F2 population in this inter-subgeneric hybrid. The conservation of microsatellite loci and synteny between Corymbia and Eucalyptus suggests there will be substantial value in exchanging information between the two groups.

Mots clés

  • Corymbia torelliana
  • Corymbia citriodora subsp. variegata
  • genetic map
  • hybrid inviability
  • genetic marker
  • tree improvement
  • marker-aided selection
Accès libre

Short Note: High Throughput Microsatellite Genotyping in Oak Species

Publié en ligne: 19 Oct 2017
Pages: 238 - 240

Résumé

Abstract

Microsatellites are widely used markers for multiple purposes in oaks. We describe a complete procedure for cheap DNA extraction and fast microsatellites genotyping by multiplex PCR. 10 loci were selected to form two multiplex kits including three loci that show a high differentiation between Quercus robur and Q. petraea. The loci were tested in three oak species and show a high mean genetic diversity of 0.84. The cumulative exclusion probability for parentage analysis was 0.999977 for single parent and 1.0 for paternity. Finally, the relatively high differentiation coefficient (Gst = 0.04) will facilitate species assignment based on genotypes in oaks.

Mots clés

  • microsatellites
  • multiplex PCR
  • Quercus
  • genetic assignment
  • parentage analysis
Accès libre

GMO Trees: Substantial promise but serious obstacles to commercialization

Publié en ligne: 19 Oct 2017
Pages: 241 - 252

Résumé

Mots clés

  • Genetic engineering
  • trees
  • transgenic
  • harvests
Accès libre

Genetic Engineering in Conifer Plantation Forestry

Publié en ligne: 19 Oct 2017
Pages: 253 - 262

Résumé

Abstract

In this review we examine the history and progression of conifer genetic engineering. The review includes the methods used, the conifer species transformed, the genes inserted and the regeneration of genetically engineered conifer trees. We cover both Biolistic® and Agrobacterium-mediated transformation, and we detail transformation events with and without plant regeneration. We show that almost all conifer transformation work uses nptII as a selective marker, and very often uidA is included as a reporter gene. Further, we show that a range of genes that are of commercial interest for forest tree plantations have been introduced, such as herbicide resistance, insect resistance and those related to wood properties. We briefly discuss the future for biotechnology in the context of socially acceptable enhanced plantation forestry and under consideration of benefits and risks.

Mots clés

  • Genetic engineering
  • conifers
  • plantation forestry
Accès libre

Engineering Forest Trees with Heavy Metal Resistance Genes

Publié en ligne: 19 Oct 2017
Pages: 263 - 268

Résumé

Abstract

Pollution of soil and water with heavy metals such as mercury, cadmium and arsenic, is a worldwide problem. Phytoremediation, the use of plants to remove, sequester or detoxify pollutants, including heavy metals, offers an environmentally-friendly alternative to engineering- based methods for remediation. Forest trees have multiple features that make them particularly useful for removal of toxic heavy metals, especially if they can be engineered with genes allowing them to handle high levels of these elements. Although still in its infancy, research with transgenic trees carrying genes allowing them to detoxify or sequester some heavy metals has already made promising progress. Most of the work to date has been performed using poplar species and hybrids, although other woody species could be equally as useful. Trees have been engineered with genes for the handling of mercury, cadmium, copper and arsenic following two main approaches, phytoextraction and phytotransformation/ phytovolatilizaton. In vitro studies have shown the transgenic trees to have enhanced abilities to tolerate and/or accumulate these metals, and preliminary results from field tests indicate that the trees are functioning. New combinations of genes involved in metal transport or conversion may further enhance the heavy metal remediation capabilities of the transgenic trees. Given the environmentally friendly application, forest trees engineered for phytoremediation may be some of the first transgenic forest trees approved for operational deployment.

Mots clés

  • phytoremediation
  • gene transfer
  • heavy metals
  • pollution
  • hardwood trees
  • genetic engineering
  • transgenic tree
  • bioremediation
  • poplar
  • willow
Accès libre

Reduction of Lignin Content by Suppression of Expression of the LIM Domain Transcription Factor in Eucalyptus camaldulensis

Publié en ligne: 19 Oct 2017
Pages: 269 - 277

Résumé

Abstract

We report a reduction of lignin content in the woody plant Eucalyptus camaldulensis by the suppression of gene expression of the LIM domain transcription factor. Previously, we identified a cDNA encoding the tobacco (Nicotiana tabacum) LIM domain transcription factor, Nt1iml, involved in lignin biosynthesis and that specifically binds to an important cis-acting element, the PALbox sequence. The orthologous Eucalyptus gene of Ntliml, namely Ecliml, was isolated from the E. camaldulensis cDNA library (84% amino acid identity). The antisense Ntliml construct with a kanamycin-resistant gene was introduced into E. camaldulensis. The transgenic Eucalyptus plants grown in the greenhouse showed decreased expression levels of severallignin biosynthesis genes, phenylalanine ammonialyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-hydroxycinnamate CoA ligase (4CL). The abnormal phenotypic changes and a 29% reduction of lignin content were observed in the line LG12, in which the transcript level of Ecliml was most1y suppressed. Ec1iml is one of the key transcription factors involved in lignin biosynthesis.

Mots clés

  • Eucalyptus camaldulensis
  • Ecliml gene
  • transgenic Eucalyptus
  • lignin
  • holocellulose
Accès libre

The Overexpression of Glutamine Synthetase in Transgenic Poplar: A Review

Publié en ligne: 19 Oct 2017
Pages: 278 - 284

Résumé

Abstract

In investigating the pivotal role of glutamine synthetase in woody plant development, we have strived to develop an understanding of the biochemical and physiological mechanisms whereby enhanced expression of glutamine synthetase (GS) in poplar contributes to vegetative growth through enhanced nitrogen use efficiency. Considerable effort has also centered on characterization of enhanced resistance of transgenic GS overexpressor lines to abiotic stresses and proposed mechanisms. This summary of our work also focuses on future applications in forest tree improvement.

Mots clés

  • poplar
  • nitrogen assimilation
  • glutamine synthetase
  • genetic engineering
  • water stress tolerance
  • anthranilate synthase
Accès libre

Faster Evaluation of Induced Floral Sterilit

Publié en ligne: 19 Oct 2017
Pages: 285 - 291

Résumé

Abstract

A major concern over the use of transgenic trees is the potential for transgene dispersal through pollen and seeds. The incorporation of sterility inducing genes into transgenic lines of trees has been proposed to reduce or even avoid gene flow of transgenes into non-transgenic interbreeding species. The evaluation of strategies for the induction of sterility in transgenic forest tree species has been hindered by their long vegetative phases. In this study an early flowering 35S::Leafy poplar line was used for the faster evaluation of the sterility construct C-GPDHC::Vst1. The combination of two transgenic approaches, one to induce early flowering and a second for the induction of sterility, allowed evaluation of this sterility strategy two years after transformation. This is a very short period of time considering the long vegetative period of seven to twenty years common in forest tree species. This approach opens opportunities for the assessment of sterility mechanisms for this plant group.

Mots clés

  • sterility
  • biosafety
  • genetic engineering
  • transgenic trees
  • Populus
  • leafy
  • stilbene synthase
  • early flowering

Planifiez votre conférence à distance avec Sciendo